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MP Board Class 6 Science Solutions

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  • Chapter 1 Food: Where Does it Come from?
  • Chapter 2 Components of Food
  • Chapter 3 Fibre to Fabric
  • Chapter 4 Sorting Materials into Groups
  • Chapter 5 Separation of Substances
  • Chapter 6 Changes Around Us
  • Chapter 7 Getting to know Plants
  • Chapter 8 Body Movements
  • Chapter 9 The Living Organisms and their Surrounding
  • Chapter 10 Motion and Measurement of Distances
  • Chapter 11 Light, Shadows and Reflections
  • Chapter 12 Electricity and Circuits
  • Chapter 13 Fun with Magnets
  • Chapter 14 Water
  • Chapter 15 Air Around Us
  • Chapter 16 Garbage In, Garbage Out

MPBSE Class 10 Science Chapter 7 Coordination In Plants Question and Answers

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MPBSE Class 10 Science Chapter 7 Coordination In Plants Question and Answers

Question 1. What are plant hormones?
Answer:

Plant hormones or phytohormones are non-nutrient diffusible chemical substances that control the activities of plants like growth, development, differentiation, movements, and other physiological processes.

Question 2. How is the movement of the leaves of a Sensitive Plant different from the movement of the shoot toward light?
Answer:

  • Leaves of sensitive plant (Mimosa pudica) droop down on being touched or shaken. It is a harmonistic or seismonastic response where the direction of movement is predetermined by the presence of a turgor cell.
  • The movement of the shoot toward light is a growth movement caused by the differential distribution of auxin.

Coordination In Plants movement of leaves of Sensitive Plant Different From Movement Of Shoot Towards Light

Question 3. Give an example of a plant hormone that promotes growth.
Answer: Auxin (IAA)/Gibberellins (GA).

Question 4. How do auxins promote the growth of a tendril around a support?
Answer:

  • In the region of contact, there is less availability of auxin as compared to the free side. Because of this, there is more growth on the free side.
  • The tendril, therefore, bends over the support. The process continues and several coils are produced.

MPBSE Class 10 Science Chapter 7 Coordination In Plants Question and Answers

Question 5. Explain the cause of shoots of the plant bending towards light.
Answer:

  • The bending of the shoot towards unilateral light is caused by the effect of light on auxin distribution.
  • There is less auxin on the illuminated side and more auxin on the shaded side. Therefore, there is more growth on the shaded side and the shoot bends in the other direction.

Question 6. What are nastic and curvature movements? Give one example of each.
Answer:

  • Nastic Movements. They are non-directional movements in which the direction of movements is determined by the structure of the responding organ, for example., the opening of flowers, haptonasty in the Sensitive Plant. Nastie movements can be due to growth or turgor changes.
  • Curvature Movements. They are directional growth movements in which the response of the plant organ is determined by the direction of the stimulus, for example., positive phototropism of shoot.

Question 7.

  1. What are plant hormones?
  2. Write two functions of auxin.

Answer:

  1. Plant Hormones. Plant hormones or phytohormones are non-nutrient diffusible chemical substances that can control various activities of plants like growth, differentiation, movements, development, and other physiological processes.
  2. Functions of Auxin.
    1. Auxin induces cell enlargement.
    2. It prevents premature falling of leaves and fruits.

Question 8.

  1. What is tropism?
  2. How do auxins promote the growth of a tendril around a support?

Answer:

  1. It is the directional curvature movement of generally cylindrical plant organs with the direction of stimulus determining the direction of movement.
  2. More auxin is present on the side of the tendril away from the point of contact. Therefore, there is more growth on the free side as compared to the contact side. The more growth on the free side causes the tendril to coil around the support.

Question 9. How is the movement of leaves of sensitive plants different from the movement of a shoot towards light?
Answer:

Coordination In Plants The Movement Of Leaves Of Sensitive Plant Different From The Movement Of A Shoot Towards Light

MPBSE Class 10 Science Chapter 7 Coordination In Plants Question and Answers

Question 10. Which plant hormone

  1. Inhibits the growth of plants
  2. Increases yield
  3. Controls cell division.

Answer:

  1. Abscisic acid
  2. Gibberellin
  3. Cytokinin.

Question 11. What is phototropism?
Answer:

Phototropism. It is the directional growth movement of curvature that occurs in plant organs in response to unilateral light.

Question 12. What is hydrotropism?
Answer:

Hydrotropism. It is the tropic or directional movement of curvature that occurs due to unilateral exposure to water. Roots are positively hydrotropic.

Question 13. If you keep the potted plant horizontally for 2-3 days, what type of movements would be shown by the shoot and root after 2-3 days? Why?
Answer:

  • The potted plant develops a geotropic response. It is different in shoot and root. The apical part of the shoot will bend upwardly.
  • It is the negative geotropic response. The apical part of the root will bend downward. It is the positive geotropic response.

Question 14.

  1. Which plant hormone is present in greater concentration in the areas of rapid cell division?
  2. Give one example of a plant growth promoter and plant growth inhibitor.

Answer:

  1. Cytokinin hormone occurs in greater concentration in the areas of rapid cell division.
  2. Growth Promoter – Auxin
    1. Growth Inhibitor – Abscisic acid (ABA).

MPBSE Class 10 Science Chapter 7 Coordination In Plants Question and Answers

Question 15. Why does the shoot of the plant bend towards light when it is kept inside a cardboard box with a small hole?
Answer:

  • Light coming from the hole functions as a unilateral stimulus. It results in passing auxin formed on the illuminated side to the shaded side.
  • The shaded side comes to have more auxin. Therefore, it shows more growth. Due to this, the shoot bends to the other side or source of light.

Question 16. What is geotropism? Describe an experiment to demonstrate positive and negative geotropism.
Answer:

Geotropism. It is a tropic or growth movement of curvature which occurs in response to the vector of gravity. The main stem is generally negatively geotropic while the main root is positively geotropic.

Question 17. List in tabular form three differences in the movement of leaves of Sensitive Plants when touched and the movement of tendrils towards the support.
Answer:

Coordination In Plants The Movement Of Leaves Of Sensitive Plant When Touched And Movement Of Tendril Towards The Support

Question 18.

  1. Name the property that causes a tendril to circle the object.
  2. What is the benefit of it?
  3. Fill in the blank_____

Coordination In Plants Harmone And Function

Answer:

  1. Thigmotropism.
  2. By circling the support, the tendril can hold the plant to support and allow it to climb further to exposing the leaves properly
  3. Inhibits growth.
    1. Cytokinin.

Question 19. How does the sensitive plant detect the touch and how do the leaves move in response?
Answer:

  • Touch is a stimulus that is converted into an electrochemical potential that reaches the bases of the leaflets and the leaf.
  • The cells at the base show efflux of K+ and water. As a result, they shrink in size and cause the folding of leaflets and drooping of leaves.

Question 20. What are plant hormones? Name the plant hormones responsible for the following :

  1. Growth of stem
  2. Promotion of cell division
  3. Inhibition of growth
  4. Elongation of cells.

Answer: Plant hormones are non-nutrient, diffusible, chemical substances that control and coordinate growth, movements, and development.

  1. Growth of Stem. Gibberellin
  2. Promotion of Cell Division. Cytokinin.
  3. Inhibition of Growth. Abscisic acid.
  4. Elongation of Cells. Auxin.

MPBSE Class 10 Science Chapter 7 Coordination In Plants Question and Answers

Question 21.

  1. Plants do not have any nervous system but yet if we touch a sensitive plant, some observable changes take place in its leaves. Explain how could this plant respond to external stimuli and how it is communicated.
  2. Name the hormone that needs to be administered to
    1. Increase the height of a dwarf plant
    2. It causes rapid cell division in fruits and seeds.

Answer:

Touching the sensitive plant creates an electrochemical impulse that travels from cell to cell quickly and reaches the bases of leaflets and leaves.

Special cells present at these bases shrink and cause bending movement of leaves and leaflets. Recovery occurs in about ten minutes when basal cells regain turgidity.

  1. Height of Dwarf Plant. Gibberellin.
  2. Rapid Cell Division. Cytokinin.

MPBSE Class 10 Science Chapter 9 Heredity Question And Answers

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MPBSE Class 10 Science Chapter 9 Heredity Question And Answers

Question 1. In a monohybrid cross between tall Pea plants TT and short Pea plants tt, a scientist obtained only tall Pea plants Tt in the F1 generation. However, on selling the F1 generation Pea plants he obtained both tall and short plants in the F2 generation. Based on the above observations and with other angiosperms also, can the scientist arrive at a law? If yes, explain the law. If not, give a justification for your answer.
Answer:

There are two possibilities for the occurrence of tall plants in the F1 generation :

  • Only the factor for tallness passed into F1 progeny. Both the alleles of tallness and shortness passed into F1 progeny but only the allele of tallness is expressing itself.
  • The second option is correct because the trait of shortness has appeared in the F2 generation.
  • Again this can happen only when the alleles for the two traits separate during gamete formation and randomly come together during fertilization.
  • The scientist could, therefore, deduce the laws out of these observations : (1) Law of dominance. (2) Law of segregation.

Question 2.

  1. List two differences in tabular form between dominant and recessive traits.
  2. What percentage or proportion of the plants in F2 generation or progeny was round in Mendel’s cross between round and wrinkled seeded Pea plants?

Differences Between Dominant And Recessive Traits

Answer: (1)

Heredity Difference between Dominant trait And recessive Trait

2. 75% of plants had round seeds while 25% of plants had wrinkled seeds. The ratio is 3: 1.

MPBSE Class 10 Chapter 9 Heredity Question And Answers

Question 3. “A trait may be inherited but may not be expressed.” Justify the statement with the help of a suitable example.
Answer:

  1. The trachea is a cylindrical conduit for air from the pharynx to the lungs.
  2. The lining epithelium captures dust particles and bacteria, expelling them forth.
  3. The trachea remains patent despite lower air pressure owing to the presence of C-shaped cartilaginous rings.

Question 4. Name the plant Mendel used for his experiment. What type of progeny was obtained by Mendel in F1 and F1 generations when he crossed tall and short plants? Write the ratios he obtained in F2 generation plants.
Answer:

Garden Pea (Pisum sativum)

F1 Generation. All tall.

F2 Generation. 3 tall: 1 short or 3: 1

or 1 pure tall: 2 hybrid tall: 1 dwarf or 1: 2: 1.

Question 5.

  1. Why did Mendel experiment to study the inheritance of two traits in garden peas?
  2. What were his findings concerning the inheritance of traits in the F1 and F2 generations?
  3. State the ratio obtained in the F2 generation in the above-mentioned experiment.

Answer:

  1. To study the independent inheritance of traits/factors of different characters.
  2. F1 Progeny. All dominant. F2 Progeny. Both parental traits as well as some new combinations or recombinants.
  3. 9 : 3 : 3: 1 where 9/16 and 1/16 are parental types while two types of recombinants appear in the ratio of 3/16 and 3/16.

Class 10 Chapter 9 Heredity Question And Answers

Question 6. A green-stemmed rose plant denoted by GG and a brown-stemmed rose plant denoted by GG are allowed to undergo a cross with each other.

1. List your observations regarding (z) the Colour of the stem in the F1 progeny and the Percentage of brown stemmed plants in F2 progeny if F1 plants are self-pollinated. The ratio of GG and Gg in F2 progeny.

2. Based on the findings of this cross, what conclusion can be drawn?

Answer:

  1. Colour in F1 Progeny. Green
  2. Percentage of Brown Stemmed Plants in F2 Progeny. 25%
  3. Ratio of GG and Gg in F2 Progeny. 1: 2.

Conclusion: The trait which is expressed in whole F1 progeny is dominant while the other trait which remains unexpressed in F1 progeny but reappears in F2 progeny is recessive.

Question 7.

  1. Why is the F1 progeny always of tall plants when a tall pea plant is crossed with a short pea plant?
  2. How is F2 progeny obtained by self-pollination of F1 progeny different from F1 progeny? Give a reason for this observation.
  3. State a conclusion that can be drawn based on this observation.

Answer:

  1. The trait or factor for tallness is dominant while the trait for shortness is recessive.
  2. The recessive trait appears in the F2 generation due to its segregation during gamete formation and the random coming together of the two traits or factors during fertilization. When two factors of shortness come together the recessive trait will appear.
  3. The traits or factors are particulate structures which do not get destroyed or blend during inheritance.

Question 8. Mendel crossed two plants with visible contrasting characteristics and found that there were no halfway characteristics in the plants of F1 progeny. Explain the reason for this observation of Mendel.
Answer:

Despite having inherited both the contrasting traits, F1 progeny shows the trait of only one parent. This is because in the hybrid (F1 plants) only one trait expresses its effect. The trait is dominant. The other trait which does not express its effect in the hybrid is called recessive.

Class 10 Chapter 9 Heredity Question And Answers

Question 9. What are chromosomes? Explain stability of the DNA of the species is ensured in sexually reproducing organisms.
Answer:

  • Chromosomes are thread-like entities based in the nucleus. Their DNA contains the genetic elements of the species. Every cell contains two copies of each chromosome.
  • In germ cells, generated post-meiosis, just one chromosome of each kind is present.
  • It may be either paternal or maternal. During fertilization, two gametes merge, reinstating the diploid state of chromosomes in the zygote and the subsequent cells of the organism derived from it.

Question 10.

  1. Name the two types of gametes produced by men.
  2. Does a male child inherit an X chromosome from his father? Justify.
  3. How many types of gametes are produced by a human female?

Answer:

  1. Men produce two types of sperms, X-carrying (gymnosperms) and Y-carrying (angiosperms) in equal proportion.
  2. No. A male child inherits the X chromosome from his mother. From their father, he inherits the Y chromosome.
  3. The female produces only one type of ova. They carry X chromosomes.

 

MPBSE Class 10 Science Chapter 6 Life Processes Question and Answers

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MPBSE Class 10 Science Life Processes Question and Answers

Question 1. (1) How many times does the blood go through the heart during one cycle in fish and why?

{2) List the respiratory pigment present in our body. Where is it present?

(3) Why are valves present in the heart and veins?
Answer:

  1. Fish have a single circulation of blood in contrast to double circulation in humans. In fish, the heart pumps the blood into the gills for purification. From the gills, the purified blood goes to the body and then comes back to the heart for pumping.
  2. Haemoglobin is the respiratory pigment. It is present in the red blood corpuscles.
  3.  Valves are present in the heart and veins to prevent the backflow of blood.

Question 2. (1) Explain in brief the mechanism of circulation of blood in the human body.

(2) “Lymph is another type of fluid involved in transportation.” Justify the statement by explaining the process.
Answer:

(1) The right atrium receives deoxygenated blood from the heart (coronary sinus), upper part of the body (superior vena cava), and middle and lower part of the body (inferior vena cava). The left atrium receives oxygenated blood from the lungs.

  • As the two atria get filled, they contract simultaneously and pour their blood into the ventricles of their side through auriculo-ventricular apertures.
  • On getting filled, the ventricles undergo systole. The left ventricle sends oxygenated blood to all body parts through the systemic aorta. The right ventricle sends deoxygenated blood to the lungs through the pulmonary arch for oxygenation.

(2) Lymph is a transportation fluid formed from tissue fluid. It is specialised to collect large size secretions and excretions which cannot directly pass into the blood, For Example., proteins, hormones, and fat. The lymph picks them and pours their contents into the blood in the region of the subclavian vein.

MPBSE Class 10 Science Life Processes Question and Answers

Question 3. (1)(A) Receives deoxygenated blood from vena cava (B) Sends deoxygenated blood to the lung through the pulmonary artery (C) Receives oxygenated blood from lungs and (D) Sends oxygenated blood to all parts of the body through the aorta.

(2) What does the blood consist of?

(3) Name the respiratory pigment in human beings and discuss its role.
Answer:

  1. (A) Right atrium (B) Right ventricle (C) Left atrium (D) Left ventricle.
  2. Blood consists of blood plasma (55%) and blood cells (45%) of three types red blood corpuscles, white blood corpuscles and blood platelets.
  3. Haemoglobin is the respiratory pigment that is found in red blood corpuscles. It carries oxygen as oxyhaemoglobin and a part of carbon dioxide as carbaminohaemoglobin.

Question 4. What is lymph? How is the composition of lymph different from blood plasma? What is the direction of its flow? List two functions of the lymphatic system.
Answer:

Lymph is a straw-coloured viscous fluid which is formed from tissue fluid and flows inside tubes called lymph vessels.

Lymph differs from blood plasma in having :

  1. 94% water instead of 92% in plasma
  2. 3.0 to 4.5 per cent protein instead of 6-8% protein in blood plasma
  3. Globulin and fibrinogen contents are lower
  4. Lymph receives a direct supply of secretion and excretion of tissues while blood obtains the same from lymph.

Direction of Flow. Unidirectional from tissues all over the body to subclavian veins.

Functions of Lymphatic System.

  1.  The lymphatic system functions as a middleman between tissue fluid and blood,
  2. It picks up germs and takes them to lymph nodes for disposal.

Question 5. (A) What do the following transport: (1) Xylem (2) Phloem (3) Pulmonary vein (4) Vena Cava?

(B) Write two points of difference between the pulmonary artery and the pulmonary vein.
Answer:

  1. (A) Xylem. Transports sap (water and mineral salts) from roots to aerial parts of the plant.
  2. Phloem. It translocates food and other solutes from a place of manufacture or storage to a place of utilisation both in upward and downward directions.
  3.  Pulmonary Vein. It carries oxygenated blood from the lungs to the left auricle.
  4. Vena Cava. It carries deoxygenated blood from different parts of the body to the right auricle. Differences between Pulmonary Artery and Pulmonary Vein

Transportation Difference Between Pulmonary Artery And Pulmonary Vein

MPBSE Class 10 Science Life Processes Question and Answers

Question 6. (1) The upward movement of water normally requires a pump in our houses but in tall trees, water rises up without any external support. Explain the mechanism.

(2) State three points of difference between the transport of materials in the xylem and phloem.
Answer:

(1) Water rises up the top of the tallest plants through the development of a negative pressure caused by loss of water in transpiration. Transpiration or loss of water in vapour form occurs from mesophyll and other cells of aerial parts.

  1. As there are innumerable numbers of cells losing water, they develop a tremendous suction pressure and withdraw water from the nearby xylem channels. This puts the water present in the xylem channel under a negative pressure of 10-20 atm.
  2. Negative pressure or pull caused by transpiration is unable to break the continuity of the water column due to the presence of cohesion force amongst water molecules and adhesion force between water and the wall of the xylem channel.
  3. The negative pressure or transpiration pull reaches the root region and forces water to move upwards. It is just like upward pulling of a cold drink with the help of a straw pipe. The mechanism of the ascent of sap through transpiration pull and cohesion force was given by Dixon and Jolly (1894).

Transportation Difference Between Transport In Xylem And Phloem

2. Force. It comes from the development of negative press- 2. It develops from the formation of turgor pressure, sure or transpiration pull.

3. Channel. The conducting channels are made of the conducting channels are formed of living sieves dead lignified elements, vessels and tracheids. tube elements.

Question 7. (1) Mention any two components of blood.

(2) Trace the movement of oxygenated blood in the body.

(3) Write the function of valves present in between atria and ventricles.

(4) Write one structural difference between artery and vein.
Answer:

  1. Composition of Blood. Blood cells—45%. Plasma—55%. Blood cells arc of three types—red blood corpuscles, white blood corpuscles and blood platelets.
  2. Movement of Oxygenated Blood. Blood is oxygenated in the lungs. Pulmonary veins carry the oxygenated blood from the lungs to the left atrium. The left atrium pours the oxygenated blood into the left ventricle. On contraction left ventricle pushes the oxygenated blood into the aorta for supply to various parts of the body.
  3.  Function of Valves. A tricuspid valve lies over the right atrioventricular aperture. A bicuspid valve occurs over the left atrioventricular aperture. They are meant to prevent the backflow of blood into the atria when the ventricles contract.
  4. Artery’ and Vein. An artery has a thicker elastic well and a narrower lumen while the vein has a thinner nonelastic wall with wider lumen and semilunar valves for preventing backflow of blood.

MPBSE Class 10 Science Life Processes Question and Answers

Question 8. (1) Write two water-conducting elements present in plants. How does water enter continuously into the root system?

(2) Explain why plants have low energy needs as compared to animals.
Answer:

  1. The two water-conducting elements of plants are tracheids and vessels. Continuous Entry of Water.
  2.  Plants have low energy requirements.

Question 9. List in tabular form three differences between blood and lymph.
Answer:

Transportation Difference Between The Blood And Lymph

Question 10. “Blood circulation in fishes is different from the blood circulation in human beings.” Justify the statement.
Answer:

Fishes have two-chambered venous hearts with a single circulation. Human beings have four-chambered arterio¬venous hearts with double circulation.

Question 11. (1) Write the correct sequence of steps followed during the journey of oxygen-rich blood from the lungs to various organs of the human body.

(2) What happens when the system of blood vessels develops a leak?
Answer:

1. Lungs → Pulmonary veins → Left atrium → Left atrial diastole followed by contraction → Left ventricle → Left ventricle diastole followed by contraction → Aorta → Various parts of body except lungs.

2. (A) Leakage will reduce blood quantity, blood pressure mid-efficiency of a pumping system,

(B) Blood coagulation at the site of length will plug the leakage

MPBSE Class 10 Science Life Processes Question and Answers

Question 13. Give Reasons

  1. Ventricles have thicker muscular walls than atria
  2. The transport system in plants is slow
  3. The circulation of blood in aquatic vertebrates differs from that in terrestrial vertebrates.
  4. During the daytime, water and minerals travel faster through the xylem as compared to the night.
  5. Veins have valves whereas arteries do not.

Answer:

  1. Thicker Walls of Ventricles.
  2. Slow Transport in Plants. Plants have a lower requirement of energy.
  3.  In aquatic vertebrates, like lush there is a single blood circulation while in terrestrial vertebrates there is double circulation.
  4. The rate of water and mineral movement is higher during the daytime due to very high transpiration.
  5. There is no forceful movement of blood in the veins. Veins possess valves to prevent backflow.

MPBSE Class 11 Chemistry Hydrogen Multiple Choice Question and Answers

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MPBSE Class 11 Chemistry Hydrogen Multiple Choice Question and Answers

Question 1. At absolute zero

  1. Only para-hydrogen exists
  2. Onlypara- hydrogen exists
  3. Both ortho- and para-hydrogen exist
  4. Neither para- nor ortho-hydrogen exists

Answer: 1. Only para-hydrogen exists

Question 2. In which of the following reaction dihydrogen acts as an oxidising agent—

  1. F2 + H2 → 2HF
  2. Cl2 + H2  → 2HC1
  3. N2 + 3H2 →2NH3
  4. 2Na + H2 → 2NaH

Answer: 4. 2Na + H2 → 2NaH

Question 3. Which of the following halogens has the least affinity towards hydrogen—

  1. I2
  2. CI2
  3. Br2
  4. F2

Answer: 1. I2

Question 4. Which of the following compounds on electrolysis produces hydrogen—

  1. dil. H2S04
  2. dil. solution of NaOH
  3. Ba(OH)2 solution
  4. KOH solution

Answer: 3. Ba(OH)2 solution

MPBSE Class 11 Chemistry MCQs Question 5. The thermal stability of Gr.-15 hydrides follows the order

  1. ASH3 > PH3 > NH3 > SbH3 > BiH3
  2. NH3 > PH3 > ASH3 > SbH3 > BiH3
  3. NH3 > AsH3 > PH3 > SbH3 > BiH3
  4. BiH3 > SbH3 > AsH3 > PH3 > NH3

Answer: NH3 > PH3 > ASH3 > SbH3 > BiH3

MPBSE Class 11 Chemistry Hydrogen Multiple Choice Question and Answers

Question 6. The correct order of vaporization enthalpy of the following hydride is

  1. NH3<PH3<AsH3
  2. AsH3<PH3<NH3
  3. PH3<AsH3<NH3
  4. NH3<AsH3<PH3

Answer: 3. PH3<AsH3<NH3

Question 7. Interstitial hydrides are formed by—

  1. S-block elements
  2. P-block elements
  3. D-block elements
  4. Intert gas elements

Answer: 3. D-block elements

Question 8. The correct descending order of thermal stability of alkali metals hydrides is—

  1. LiH > NaH > KH > RbH > CsH
  2. CsH > RbH > KH > NaH > LiH
  3. NaH > KH > LiH > CsH > RbH
  4. CsH > LiH > KH > NaH > RbH

Answer: 1. LiH > NaH > KH > RbH > CsH

MPBSE Class 11 Chemistry MCQs  Question 9. Solubility of NaClin the solvents H20 and DaO is

  1. Equal in both
  2. More in D20
  3. More in H20
  4. Only in H20

Answer: 3. More in H20

Question 10. The degree of hardness of 1L sample water containing 0.002 mol MgS04 is

  1. 20 ppm
  2. 200 ppm
  3. 2000ppm
  4. 120ppm

Answer: 2. 200 ppm

Question 11. Which of the following reacts with water to produce electron-precise hydrides—

  1. Ca3P2
  2. AI4C3
  3. Mg3N2
  4. None of these

Answer: 2. Al4C3

Hydrogen Class 11 MCQ Question 12. Which of the following couples reacts with water to produce the same gaseous product—

  1. K and K02
  2. K and K02
  3. Na and Na202
  4. Ba and Ba02

Answer: 2. K and K02

Question 13. Which of the following compounds contain free hydrogen

  1. Water
  2. Marsh gas
  3. Water gas
  4. Acid

Answer: 3. Water gas

Question 14. Which of the following reacts with metallic sodium to produce hydrogen—

  1. CH4
  2. C2H6
  3. C2H4
  4. C2H2

Answer: 4. C2H2

Question 15. Semi-water gas is

  1. CO + H2 + N2
  2. H2 + CH4
  3. CO + H2+ O2
  4. CO + H2

Answer: 1. CO + H2 + N2

Question 16. Which of the following metals does not react with cold water liberates H2  with boiling water

  1. Na
  2. K
  3. Pt
  4. Fe

Answer: 4. Fe

Question 17. Volume of ’10 volume’ H202 required to convert 0.01 mol PbS into PbS04 is—

  1. 11.2 mL
  2. 22.4 mL
  3. 33.6 mL
  4. 44.8 mL

Answer: 4. 44.8 mL

Hydrogen Class 11 MCQ Question 18. On dilution of H202, the value of dielectric constant

  1. Increases
  2. Remains same
  3. Decreases
  4. None of these

Answer: 1. Increases

Question 19. By which of the following water gets oxidized to oxygen

  1. Cl02
  2. KMn04
  3. H202
  4. F2

Answer: 4. F2

Question 20. Which of the following does not get oxidized by H202

  1. Na2S03
  2. PBS
  3. KI
  4. O3

Answer: 4. O3

Question 21. The temperature at which the density of D20 is maximum is

  1. 9°C
  2. 11.5°C
  3. 15.9°C
  4. 20°C

Answer: 11.5°C

Question 22. Which of the following undergoes disproportionation reaction with water—

  1. S03
  2. F2
  3. Cl2
  4. N2

Answer: 2. F2

Hydrogen Class 11 MCQ Question 23. Which of the following undergoes disproportionation reaction with water—

  1. S03
  2. F2
  3. Cl2
  4. N2

Answer: 3. Cl2

Question 24. The non-inflammable hydrides

  1. NH3
  2. PH3
  3. ASH3
  4. SbH3

Answer: 1. NH3

Question 25. The triple point of water is

  1. 203K
  2. 193K
  3. 273K
  4. 373K

Answer: 3. 273K

Question 26. The process by which hydrogen is prepared by the reaction of silicon, iron alloy, and NaOH is

  1. Woodprocess
  2. Haber’s process
  3. Silicol process
  4. Bosch process

Answer: 3. Silicol process

Question 27. An element reacts with hydrogen to form a compound A, which in reaction with water liberates hydrogen again. The elements—

  1. Cl
  2. CS
  3. Se
  4. N2

Answer: 2. CS

Question 28. Only one element of which of the following groups forms a metal hydride

  1. Gr-6
  2. Gr-7
  3. Gr-8
  4. Gr-9

Answer: 1. Gr-6

Question 29. An acidic solution of which of the following turns orange in the presence of H202 —

  1. Ba02
  2. Na202
  3. Ti02
  4. Pb02

Answer: 3. Ti02

Question 30. In the following reaction the isotopic oxygens \(2 \mathrm{MnO}_4^{-}+3 \mathrm{H}_2 \mathrm{O}_2^{18} \rightarrow 2 \mathrm{MnO}_2+3 \mathrm{O}_2+2 \mathrm{H}_2 \mathrm{O}+2 \mathrm{OH}^{-}\)

  1. Both get converted into 02
  2. Both get converted into oh
  3. Both get converted into more
  4. One of them gets converted to 02, another to mn02

Answer: Both get converted into 02

Question 31. X on electrolysis produces Y which on vacuum distillation produces H202. The numbers of peroxo linkage present X and Y are

  1. 1,1
  2. 1,2
  3. 0>1
  4. 0,0

Answer: 3. 0>1

Question 32. The compound which on electrolysis in its molten or liquid state liberates hydrogen at the anode is

  1. NaOH
  2. CaH2
  3. HC1
  4. H20

Answer: 2. CaH2

Question 33. Which of the following couples exhibit the maximum isotope effect

  1. H D
  2. O O
  3. CI CI
  4. C C

Answer: 1. H D

Question 34. Which of the following emits by tritium

  1. Neutron
  2. Ray
  3. Particle
  4. Particle

Answer: 3. Particle

MPBSE Class 11 Chemistry MCQs Question 35. Oxidation of benzene by H202 in the presence of ferrous sulfate produces

  1. Pheno
  2. Cyclohexane
  3. Anisole
  4. Benzaldehyde

Answer: 1. Pheno

Question 36. The oxidation state of Cr in the product obtained by the reduction of K2Cr20? by atomic hydrogen is

  1. +6
  2. +2
  3. 0
  4. +3

Answer: 4. +3

Question 37. Which of the following does not get reduced by H2 in its aqueous solution

  1. Cu2+
  2. Fe3+
  3. Zn2+
  4. Ag+

Answer: 3. Zn2+

Question 38. Which of the following compounds has a similar odor as that of H202

  1. Caustic soda
  2. Chloroform
  3. Alcohol
  4. Nitric acid

Answer: 4. Nitric acid

Question 39. Which of the following compounds reacts with atomic hydrogen to form formaldehyde

  1. CO
  2. C02
  3. CH4
  4. C2H2

Answer: 1. CO

Question 40. Which of the following isotopes of hydrogen is the most reactive

  1. H
  2. H
  3. H
  4. All the isotopes are equally reactive

Answer: 1. H

MPBSE Class 11 Chemistry MCQs Question 41. When equal amounts of Zn are allowed to react separately with excess H2S04 and excess NaOH, then the ratio of the volumes of hydrogen produced for the first and the second case respectively

  1. 1:2
  2. 2:1
  3. 4:9
  4. 1:1

Answer: 4. 1:1

Question 42. Which of the following hydrides of s-block elements have a polymeric structure

  1. LiH
  2. BeH2
  3. No
  4. MgH2

Answer: 2. BeH2

Question 43. Which of the following statements is true—

  1. Ifz= 15, the element forms a covalent hydride
  2. Ifz= 23, the element forms an ionic hydride
  3. Ifz= 19, the element forms an ionic hydride
  4. Ifz= 44, the element forms metalic hydride

Answer: 1. Ifz= 15, the element forms a covalent hydride

Question 44. Which of the following hydrides are polynuclear hydrides

  1. No
  2. C3H8
  3. N2H4
  4. HF

Answer: C3H8

Question 45. Which of the following statements is correct

  1. Metallic hydrides are hydrogen-deficient
  2. Metallic hydrides are conductors of heat and electricity
  3. Ionic hydrides in their solid state do not conduct electricity
  4. Ionic hydrides on electrolysis in their molten state produce h2 at the cathode.

Answer: 1. Metalic hydrides are hydrogen deficient

Question 46. Which of the following ions get exchanged with Na+ ion of zeolite when zeolite is added to thehard water

  1. H+ ion
  2. Ca2+ ion
  3. So+ ion
  4. Mg2+ ion

Answer: 2. Ca2+ ion

MPBSE Class 11 Chemistry MCQs Question 47. Which of the following reactions are neurolysis

  1. 2Na + 2D20 → 2NaOD + D2
  2. AlClg + 3D20 →Al(OD)3 + 3DC1
  3. Ca + 2D20→ Ca(OD)2 + D2
  4. Fe2(S4)3 + 6D20-> 2Fe(0D)3 + 3D2S04

Answer: 2. AlClg + 3D20→ Al(OD)3 + 3DC1

Question 48. Which of the following reactions are redox reactions

  1. H2O + so2 → H2SO3
  2. CaO + H20 → Ca(OH)2
  3. 2Na + 2H20 → 2NaOH + H2
  4. 2F2 + 2H20 → 02 + 4HF

Answer: 3. 2Na + 2H20 → 2NaOH + H2

Question 49. In which of the following reactions H202 acts as a reductant—

  1. CgHg + H202 → CgHgOH + H220
  2. PbS + 4H202 → PbS04 + 4H20
  3. Na0Br +H202 → NaBr + H20 + 02
  4. 2Mn04 +6H+ + 5H202 → 2Mn2+ + 8H20 + 502

Answer: 3. Na0Br +H202 → NaBr + H20 + 02

Question 50. Which of the properties are the same for a metal and its hydride

  1. Hardness
  2. Electrical conductance
  3. Magnetic property
  4. Metallic lustre

Answer: 1. Hardness

Question 51. The correct orders are—

  1. H2 < D2 < T2 : boilingpoint
  2. H2 < D2 < T2 : freezing point
  3. H2 < D2 < T2 : latent heat ofvaporisation
  4. T2O > H20 > D20 : dissociation constant

Answer: 1. H2 < D2 < T2 : boilingpoint

Question 52. Which of the following reacts with zinc to produce hydrogen gas

  1. dil.HCl
  2. cold water
  3. hot NaOH solution
  4. cone. H2S04

Answer: 2. cold water

Question 53. Which of the following properties has a greater magnitude in D20 than that in H20

  1. Viscosity
  2. Surface tension
  3. dielectric constant
  4. latent heat of vaporisation

Answer: 2. Viscosity

Question 54. Which of the following metal hydrides get reduced by hydrogen

  1. CuO
  2. Pb304
  3. Na202
  4. MgO

Answer: 1. CuO

Question 55. Multimolecular covalent hydrides of s-block are

  1. LiH
  2. BeH2
  3. NaH
  4. MgH2

Answer: 2. BeH2

MPBSE Class 11 Chemistry MCQs Question 56. The oxidation numbers of the most electronegative element in the product were obtained due to the reaction between Ba02 and dil. H2S04 are—

  1. -1
  2. 0
  3. -2
  4. +1

Answer: 1. -1

Question 57. Which of the following compounds decreases the rate of decomposition of H202 —

  1. CO(NH2)2
  2. Mn02
  3. PbNHCOCH3
  4. (COOH)2

Answer: 1. CO(NH2)2

Question 58. Which of the following produces H202 on hydrolysis

  1. Pemitricacid
  2. Perchloric acid
  3. Perdisulphuric acid
  4. Caro’s acid

Answer: 1. Pemitricacid

Question 59. Choose the correct statements

  1. The concentration of 20 volume H202 solution is 60.7g L-1
  2. volume strength of 2(N)H202 solution is 15
  3. volume strength of 2(N)H202 solutions 11.2
  4. The concentration of the 20-volume H202 solution is 50.7g. L-1

Answer: 1. The Concentration of 20-volume H202 solution is 60.7g L-1

Question 60. Choose the correct alternative—

  1. a mixture of HCl and HCIO is formed when chlorine reacts with cold water
  2. arrange color of K2Cr207 solution turns blue when it reacts with H202
  3. under low pressure, isopropyl alcohol reacts with a small amount of H202 to produce formaldehyde
  4. hydrolith produces black coloured product when it reacts with PbS04

Answer: 1. a mixture of HC1 and HCIO is formed when chlorine reacts with cold water

Question 60. Which of the following alternatives is not true—

  1. The correct order of reactivity of h2 towards the halogens
  2. Is: cl2 > br2 > i2 > f2
  3. The concentration of h202 used in rockets is 90%
  4. H2 gets more readily absorbed on the surface of metal than d2
  5. Conversion of atomic hydrogen into molecular hydrogens is an exothermic process

Answer: 1. Correct order of reactivity of h2 towards the halogens

MPBSE Class 11 Physics Chapter 12 Thermal Expansion Multiple Choice Question And Answers

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Calorimetry And Thermal Expansion Multiple Choice Question And Answers

Question 1. The amount of heat required to change the state of 1 kg of substance at constant temperature is called

  1. Kilocal
  2. Calorie
  3. Specific heat
  4. Latent heat

Answer: 4. latent heat

Question 2. The water equivalent of a 400 g copper calorimeter (specific heat = 0.1 cal/gºC)

  1. 40 g
  2. 4000 g
  3. 200 g
  4. 4 g

Answer: 1. 40 g

Question 3. Heat required to convert 1 g of ice at 0ºC into steam at 100ºC is

  1. 100 cal
  2. 0.01 cal/ºC
  3. 720 cal
  4. 1 kilocal

Answer: 3. 720 cal

Question 4. The thermal capacity of 40 g of aluminum (specific heat = 0.2 cal/gmºC)

  1. 40 cal/ºC
  2. 160 cal/ºC
  3. 200 cal/ºC
  4. 8 cal/ºC

Answer: 5. 8 cal/ºC

Class 11 Physics Thermal Expansion MCQs Question 5. The boiling water is changing into steam. Under this condition, the specific heat of water is

  1. Zero
  2. One
  3. Infinite
  4. Less than one

Answer: 3. Infinite

Question 6. One kg of ice at 0ºC is mixed with 1 kg of water at 10ºC. The resulting temperature will be

  1. Between 0ºC and 10ºC
  2. 0ºC
  3. Less than 0ºC
  4. Greater than 0ºC

Answer: 2. 0ºC

Question 7. If 10g of ice at 0ºC is mixed with 10g of water at 40ºC, the final mass of water in the mixture is

  1. 10 g
  2. 15 g
  3. 18 g
  4. 20 g

Answer: 2. 15 g

Question 8. Water is used to cool the radiators of engines in cars because:

  1. Of its low boiling point
  2. Of its high specific heat
  3. Of its low-density
  4. Of its easy availability

Answer: 2. Of its high specific heat

Question 9. Steam at 100ºC is passed into 2.0 kg of water contained in a calorimeter of water equivalent to 0.02 kg at 15ºC till the temperature of the calorimeter and its contents rise to 90ºC. The mass of steam condensed in kg is

  1. 0.301
  2. 0.280
  3. 0.60
  4. 0.02

Answer: 2. 0.280

Class 11 Physics Thermal Expansion MCQs Question 10. A small quantity, mass m, of water at a temperature θ (inºC) is poured onto a large mass M of ice which is at its melting point. Ιf c is the specific heat capacity of water and L is the latent heat of fusion of ice, then the mass of ice melted is given by :

  1. \(\frac{\mathrm{ML}}{\mathrm{mc} \theta}\)
  2. \(\frac{\mathrm{mc} \theta}{\mathrm{ML}}\)
  3. \(\frac{\mathrm{Mc} \theta}{\mathrm{L}}\)
  4. \(\frac{\mathrm{mc} \theta}{\mathrm{L}}\)

Answer: 4. \(\frac{\mathrm{mc} \theta}{\mathrm{L}}\)

Question 11. 20 gm ice at –10 ºC is mixed with m gm steam at 100 ºC. Minimum value of m so that finally all ice and steam converts into water. (Use sice=0.5 cal/gmºC, swater=1 cal/gmºC,L (melting)=80 cal/gm and L (vaporization) = 540 cal/gm)

  1. \(\frac{85}{32} \mathrm{gm}\)
  2. \(\frac{85}{64} \mathrm{gm}\)
  3. \(\frac{32}{85} \mathrm{gm}\)
  4. \(\frac{64}{85} \mathrm{gm}\)

Answer: 1. \(\frac{85}{32} \mathrm{gm}\)

Question 12. 300 calories of heat is supplied to raise the temperature of 50 gm of air from 20°C to 30°C without any change in its volume. Change in internal energy per gram of air is

  1. Zero
  2. 0.6 calories
  3. 1.2 calories
  4. 6.0 calories

Answer: 4. 6.0 calories

Question 13. How much heat energy is gained when 5 kg of water at 20°C is brought to its boiling point? (Specific heat of water = 4.2 kg-1C-1)

  1. 1680 kJ
  2. 1700 kJ
  3. 1720 kJ
  4. 1740 kJ

Answer: 1. 1680 kJ

Question 14. Two rigid boxes containing different ideal gases are placed on a table. Box A contains one mole of nitrogen at temperature T0, While Box B contains one mole of helium at temperature (7/3) T0. The boxes are then put into thermal contact with each other and heat flows between them until the gases reach a common final temperature (ignore the heat capacity of boxes). Then, the final temperature of the gases, Tf, in terms of T0 is

  1. \(\mathrm{T}_{\mathrm{f}}=\frac{7}{3} \mathrm{~T}_0\)
  2. \(T_f=\frac{3}{2} T_0\)
  3. \(T_f=\frac{5}{2} T_0\)
  4. \(T_f=\frac{3}{7} T_0\)

Answer: 2. \(T_f=\frac{3}{2} T_0\)

Class 11 Physics Thermal Expansion MCQs Question 15. Compared to a burn due to water at 100°C, a burn due to stem at 100°C is

  1. More dangerous
  2. Less dangerous
  3. Equally dangerous
  4. None of these

Answer: 1. More Dangerous

Question 16. Their moment should have its heat capacity small. If P is mercury thermometer, Q is resistance thermometer and R is thermocouple type then

  1. P is best, R worst
  2. R is best, P worst
  3. R is best, Q worst
  4. P is best, Q worst

Answer: 3. R is best, Q worst

Question 17. If 1g of steam is mixed with 1 g of ice, then the resultant temperature of the mixture is :

  1. 270°C
  2. 230°C
  3. 100°C
  4. 50°C

Answer: 3. 100°C

Question 18. The amount of heat required to convert a gram of ice at 0ºC into steam at 100ºC will be –

  1. 716 cal
  2. 500 cal
  3. 180 cal
  4. 100 cal

Answer: 1. 716 cal

Question 19. 10 grams of ice at 0ºC is mixed with 10 grams of water at 20ºC. The final temperature of the mixture will be

  1. 50ºC
  2. 10ºC
  3. 0ºC
  4. 15ºC

Answer: 3. 0ºC

Class 11 Physics Thermal Expansion MCQs  Question 20. The amount of heat required to change 1 gm (0ºC) of ice into water of 100°C, is :

  1. 716 cal
  2. 500 cal
  3. 180 cal
  4. 100 cal

Answer: 3. 180 cal

Question 21. The latent heat of steam is 536 cal/gm, then its value in joule/kg is:

  1. 2.25 × 106
  2. 2.25 × 103
  3. 2.25
  4. None of these

Answer: 1. 2.25 × 106

Question 22. At 100ºC, the substance that causes the most severe burn is –

  1. Oil
  2. Steam
  3. Water
  4. Hot air

Answer: 2. Steam

Question 23. The SI unit of the mechanical equivalent of heat is –

  1. Joule × calorie
  2. Joule/calorie
  3. Calorie×erg
  4. Erg/calorie

Answer: 2. Joule/calorie

Question 24. Volume expansion coefficient of a gas at constant pressure equal to:

  1. Temperature
  2. Proportional to square root of temperature
  3. Inversely proportional to the square root of temperature
  4. Inversely proportional to temperature

Answer: 4. Inversely proportional to temperature

Question 25. 50 gm ice at 0ºC in an insulator vessel, 50 g water of 100ºC is mixed in it, then the final temperature of the mixture is (neglecting the heat loss) :

  1. 10ºC
  2. 0º << Tm< 20ºC
  3. 20ºC
  4. Above 20ºC

Answer: 1. 10ºC

Class 11 Physics Thermal Expansion MCQs Question 26. A bottle is filled with water at 30ºC. When it is taken on the moon then :

  1. Water will freeze
  2. Water will boil
  3. Water will decompose in hydrogen and oxygen
  4. Nothing will happen to the water

Answer: 4. Nothing will happen to the water

Question 27. Work done in converting one gram of ice at –10ºC into steam at 100ºC is –

  1. 3045 J
  2. 6056 J
  3. 721 J
  4. 616 J

Answer: 1. 3045 J

Question 28. The ratio of radii of two spheres of the same material is 1: 4, then the ratio of their heat capacities is

  1. \(\frac{1}{4}\)
  2. \(\frac{1}{16}\)
  3. \(\frac{1}{32}\)
  4. \(\frac{1}{64}\)

Answer: 4. \(\frac{1}{64}\)

Question 29. Heat given to a body which raises its temperature by 1°C is :

  1. Water equivalent
  2. Thermal capacity
  3. Specific heat
  4. Temperature gradient 32453351

Answer: 2. Thermal capacity

Question 30. If mass-energy equivalence is taken into account, when water is cooled to form ice, in an isolated system the mass of water should:

  1. Increase
  2. Remain unchanged
  3. Decrease
  4. First increase then decrease

Answer: 1. Increase

MPBSE Class 11 Chemistry Notes For Entropy

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MPBSE Class 11 Chemistry Notes For  Concept Of Entropy

We have already seen that enthalpy is not the ultimate criterion of spontaneity. Another factor such as the randomness of the constituting particles (molecules, atoms, or ions) of the system may also be responsible for determining the spontaneity of a process.

Rudolf Clausius introduced a new thermodynamic property or state function known as entropy, from the Greek word ‘trope’ meaning transformation. It is denoted by the letter ‘S’. The entropy of a system is a measure of the randomness or disorderliness of its constituent particles.

The more disordered or random state of a system, the higher the entropy it has. Thus, from the molecular point of view, the entropy of a system can be defined below.

Class 11 Chemistry Notes For Entropy

The entropy of the system is a thermodynamic property that measures the randomness or disorderliness of the constituent particles making up the system.

According to the above definition, it may seem that entropy is related to the individual constituent particle of the system. However, thermodynamics, whose framework is based on a macroscopic approach, is not concerned with the existence and the nature of the constituent particles of the system.

Entropy, which is a macroscopic property, is in no way related to the behavior of the individual atoms or molecules of a system, instead, it reflects the average behavior of a large collection of atoms or molecules by which a system usually consists.

MPBSE Class 11 Chemistry Notes For  Mathematical interpretation of entropy

Since heat (q) is not a state function, the exchange of heat (5q) i.e., the amount of heat absorbed or rejected by a system during a process is not an exact differential.

But in a reversible process, the ratio of the heat exchanged between the system and surroundings \(\frac{\delta q_{r e v}}{T}\) to an absolute temperature at which the heat exchanger takes place is an exact differential. Hence, the quantity indicates the change ofa state function. This function is called entropy (S). Therefore, the change in entropy,

⇒ \(d S=\frac{\delta q_{r e v}}{T}=\frac{\begin{array}{c}
\text { Reversible heat transfer between } \\
\text { system and its surroundings }
\end{array}}{\begin{array}{c}
\text { Temperature (K) at which } \\
\text { heat is transferred }
\end{array}}\) …………………………….(1)

a reversible process, the state of a system changes from state 1 (initial state) to state 2 (final state), then the change in entropy (AS) in the process can be determined by integrating the equation

⇒ \(\int_1^2 d S=\int_1^2 \frac{\delta q_{r e v}}{T} \text { or, } S_2-S_1=\int_1^2 \frac{\delta q_{r e v}}{T} \text { or, } \Delta S=\int_1^2 \frac{\delta \tilde{q} q_{r e t}}{T}\)

For the process occurring at a constant temperature, the change in entropy, \([\Delta S=\frac{1}{T} \int_1^2 \delta q_{r e v}=\frac{q_{r e v}}{T}.\)

Class 11 Chemistry Notes For Entropy

It is not possible to define entropy; however, we can define the change in entropy of a system ( dS or AS) undergoing a reversible process. It is defined as the ratio of reversible heat exchange between the system and its surroundings to the temperature at which the heat exchange takes place.

The relation tells us for a given input of heat into a system, the entropy of the system increases more at a lower temperature than at a higher temperature.

The randomness in a system is a measure of its entropy. The more randomness the more entropy. Therefore, for a given input of heat into a system, the randomness of the system increases more when heat is added to the system at a lower temperature than at a higher temperature.

MPBSE Class 11 Chemistry Notes For  Characteristics of entropy

The entropy of a system quantifies the unpredictability of its constituent particles. Entropy is a state function as its value for a system relies solely on the current state of the system, and its change (ΔS) during a process is determined exclusively by the beginning and final states of the system, independent of the pathway taken to execute the process.

  • Being a state function, it is a quantity that is independent of the path taken. Entropy is an extended property, as its value for a system is contingent upon the quantity of matter within the system.
  • The entropy of the cosmos grows in a spontaneous process (ΔSuniv > 0) and decreases in a non-spontaneous process (ΔSuniv < 0). At equilibrium, the change in entropy of the system is zero. At absolute zero, the entropy of a pure, perfect crystalline solid is zero.

MPBSE Class 11 Chemistry Notes For Physical significance of entropy

There exists a relationship between the entropy of the system and the randomness of its constituent particles (atoms, ions, or molecules).

The entropy of a system increases or decreases with the increase or decrease in randomness of the particles constituting the system. Therefore, entropy is the measure of the randomness of the constituent particles in a system. this is the physical significance of entropy.

Class 11 Chemistry Notes For Entropy

The change in entropy is defined in terms of a reversible process, for which it is defined as

⇒ \(d S=\frac{\delta q_{r e v}}{T}\) where 8qrev) Is the reversible exchange of heat between a system and its surroundings at 7’K. in case of an irreversible process, the change in entropy

⇒ \(d S \neq \frac{\delta q_{i r r}}{T}\) where 5<](rr represents irreversible exchange of heat between a system and its surroundings at 7’K.

As entropy is a state function, its change in a particular process does not depend on the nature of the process. Thus, the change in entropy in a process carried out reversibly is the same as the change in entropy that occurs if the same process is carried out irreversibly.

MPBSE Claass 11 Chemistry Notes For Entropy

MPBSE Class 11 Chemistry Notes For  Unit of Entropy

In the CGS system, the unit of entropy = cal.deg-1, while the unit of entropy in SI = J. K-1

Change In Entropy Of The System In Some Processes

When a system undergoes a process, its change in entropy in the process is ΔS = S2 – S1; where S1 and S2 are the entropies of the initial and final states of the system respectively, in a process.

In a process, if S2 > S1, then ΔS is positive. This means that the entropy of a system increases in the process. For example, the melting of ice or vaporization of water is associated with an increase in the entropy of the system, so AS is involved in these processes.

If S2 < S1, then ΔS is negative, indicating that the entropy of the system decreases in the process. For example, when ice is formed from liquid water or water is formed from water vapor, the entropy of the system decreases i.e., ΔS =-ve.

MPBSE Class 11 Chemistry Notes For  Change in entropy in a chemical reaction

In any chemical reaction, the initial entropy (S1) of the system means the total entropy of the reactants, and the final entropy of the system (S2) means the total entropy of the products.

Hence, the change in entropy in a chemical reaction, ΔS = \(S_2-S_1^{3 i}=\sum S_{\text {products }}-\sum S_{\text {reactants }} \text {, where, } \sum S_{\text {reactants }}\text { and } \sum S_{\text {products }}\)

Change in entropy of the system in a cyclic process:

The change in entropy of the system in any process, ΔS = S2– S1 where S1 and S2 are the initial and final entropies of the system, respectively. Because entropy is a state function, and in a cyclic process the initial and the final states of a system are the same, = S2, and the change in entropy ofthe system, ΔS = 0.

MPBSE Class 11 Chemistry Notes For  Change in entropy of the system in a reversible adiabatic process

In an adiabatic process, heat exchange does not occur between a system and its surroundings. Therefore, in a reversible adiabatic process, qrev = 0 and the change in entropy ofthe system in this process.

⇒ \(d S=\frac{\delta q_{r e v}}{T}=\frac{0}{T}=\mathbf{0} \text { or, } d s=0 \text { or, } \Delta S=0\)

Therefore, the change in entropy of a system undergoing a reversible adiabatic process is zero, i.e., the entropy of a system remains the same in an adiabatic reversible change. Owing to this a reversible adiabatic process is sometimes called an isentropic process.

Class 11 Chemistry Notes For Entropy

Change in entropy of the system in an irreversible adiabatic process: Like reversible adiabatic process, heat exchange does not also occur in an irreversible adiabatic process. However, it can be shown that in an irreversible adiabatic process, the entropy change of a system is always positive, i.e., ΔS > 0.

MPBSE Class 11 Chemistry Notes For  Change in entropy of the system in an isothermal reversible process

Let us consider, a system change from state 1 to state 2 in an isothermal reversible process. Therefore, in this process, the change in entropy of the system.

⇒ \(\int_1^2 d S=\int_1^2 \frac{\delta q_{r e v}}{T} \text { or, } S_2-S_1=\frac{1}{T} \int_1^2 \delta q_{r e v} \text { or, } \Delta S=\frac{q_{r e v}}{T}\)

Since T= constant as the process is isothermal]

MPBSE Class 11 Chemistry Notes For  Change in entropy during a phase transition

Melting of a solid, vaporization of a liquid, solidification of a liquid, condensation of vapor, etc. are some examples of phase transition.

At a particular temperature, a phase transition occurs at a constant pressure. The temperature remains unaltered during the transition although heat is exchanged between the system and the surroundings.

Class 11 Chemistry Notes For Entropy

The phase transition can be considered as a reversible process. If qrev of heat is absorbed during a phase transition at constant pressure and 7’K, then the change in entropy, of the system. As the process is occurring at constant pressure

⇒ \(q_{\text {re }}=q_p=\Delta H.\).

hence \(\Delta s=\frac{\Delta n}{r}\) \(\Delta s=\frac{\Delta n}{r}\) ……………………….(1)

MPBSE Class 11 Chemistry Notes For  The entropy of fusion

It In defined as the change in entropy associated with the transformation of one mole of a solid substance into its liquid phase at its melting point

According to equation (1) \(\Delta S_{f u s}=\frac{\Delta H_{f u s}}{T_f}\)

where ΔHvap= the enthalpy of fusion = die heat required for the transformation of 1 mol of a solid at its melting point into 1 ml of liquid and T1= melting point (K) of the given solid As the fusion of a solid substance is an endothermic process (Le, A> 0 ), the change in entropy due to fusion (ΔSvap) is always positive.

Class 11 Chemistry Notes For Entropy

In the solid phase of a substance, the constituent particles are held in an ordered state. The degree of orderliness is less in the liquid phase as the particles in the liquid have freedom of motion. This is why, when a solid melts, the randomness within the system increases, causing an increase in the entropy of the system.

Example: The enthalpy of fusion of ice at 0°C and 1 atm. Therefore, the change in entropy during the transformation of 1 mol of ice into 1 mol of water at 0°C and 1 atm is-

MPBSE Class 11 Chemistry Notes For  Entropy of vaporization

It is defined as the change in entropy when one mole of a liquid at its boiling point changes to its vapor phase.

Where ΔH = the enthalpy of vaporization = the heat required for the transformation of 1 mol of liquid at its boiling point into 1 mol of vapor and Tb = boiling point ofthe liquid (K).

As the vaporization of a liquid is an endothermic process [i.e., \(\Delta H_{v a p}>0\)), the change in entropy in a vaporization process (ΔSvap) is always positive. When a liquid vaporizes, the molecular randomness in the system increases as the molecules in the vapor phase have more freedom of motion thus they have in the liquid phase. As a result, the vaporization of a liquid always leads increase in the entropy ofthe system.

Example: The enthalpy of vaporization of water at 100°C and 1 atm (ΔHvap) = 40.4 kj .mol-1

. Thus, the change in entropy due to the transformation of 1 mol of water into 1 mol of water vapor at 0°C temperature and 1 atm pressure is

⇒ \(\Delta S_{\text {vap }}=\frac{\Delta H_{\text {vap }}}{T_b}=\frac{40.4 \mathrm{~kJ} \cdot \mathrm{mol}^{-1}}{373 \mathrm{~K}}=108.3 \mathrm{~J} \cdot \mathrm{K}^{-1} \cdot \mathrm{mol}^{-1}\)

Class 11 Chemistry Notes For Entropy

Entropy change in an isothermal reversible expansion or compression of an ideal gas

Let, n mol of an ideal gas undergoes an isothermal reversible expansion from its initial state (P1 V1 to the final state (P2, V2). The equation showing the change in entropy of the gas in the process can be derived.

The result of this derivation gives the relation—

⇒ \(\Delta S=n R \ln \frac{V_2}{V_1}=2.303 n R \log \frac{V_2}{V_1}=2.303 n R \log \frac{P_1}{P_2}\)

As the gas expands, V2 > V2 (or, P1> P2 ), so according to the equation [1], the change in entropy (AS) of the gas due to its expansion is positive i.e., the entropy of the system increases.

If the isothermal reversible compression of the same amount of gas causes a change in the state of the gas form (P1 V1 to (P2, V2), then the change in entropy of the gas is given by

⇒ \(\Delta S=n R \ln \frac{V_2}{V_1}=2.303 n R \log \frac{V_2}{V_1}=2.303 n R \log \frac{P_1}{P_2}\)

As the gas is compressed, V2 < V1 (or P2> P1 ), According to equation [2], the change in entropy (AS) of the gas due to its compression is negative, i.e., the entropy of the system decreases.

Class 11 Chemistry Notes For Entropy

If the volume of a gas is increased, the gas molecules will get more space for their movement i.e., the gas molecules will move in greater volume. As a result, the randomness of the gas molecules as well as the entropy ofthe system (gas) will increase.

Thus, the entropy of a gas increases with the increase of its volume. On the other hand, the entropy of a gas decreases with the decrease of its volume.

MPBSE Class 11 Chemistry Notes For  Change in entropy of the surroundings

When a system exchanges heat with its surroundings, the entropy of the system as well as its surroundings changes.

To calculate the change in entropy of the surroundings, the given points are to be considered:

Surroundings are so large compared to one system that they serve as a heat reservoir without undergoing any temperature change.

Surroundings absorb or release heat reversibly, and during these processes, the temperature and pressure of the surroundings remain almost the same In a process at TK, if the amount of heat released by the system to the surroundings is sys, then the amount of heat absorbed by tire surroundings = -guys (the sign of q is -ve).

Therefore, in this process, the change in entropy of the surroundings \(\Delta S_{s u r r}=-\frac{q_{s y s}}{T}\)

Class 11 Chemistry Notes For Entropy

Hence, the entropy of the surroundings increases if heat is released by the system to the surroundings.

In a process at T K, if the amount of heat absorbed by the system from the surroundings is q, then the amount of heat released by the surroundings will be -qsys (the sign of qsys is +ve ). So, in this process, the change in entropy of the surroundings, \(\Delta S_{\text {surr }}=-\frac{q_{s y s}}{T}.\)

Hence, the entropy of the surroundings decreases if heat is absorbed by the system from the surroundings

MPBSE Class 11 Chemistry Notes For  Standard entropy change in a chemical reaction

Standard molar entropy of a substance:

Entropy of 1 mol of a pure substance at a given temperature (usually 25°C) &1 atm pressure is termed as the standard molar entropy of that substance.

It is denoted by S° and its unit is J. K-1.mol-1.

Standard entropy change in a chemical reaction (ΔS°):

In a chemical reaction, the change in standard entropy, ΔS° = total standard entropies of the products – total standard entropies of the reactants i.e.,

⇒  \(\Delta s^0=\sum n_i s_i^0-\sum n_j s_j^0\)

Where Soi and Soj are the standard entropy of the i -tit product and j -th reactant, respectively. n1 and n2 are the number of moles of the Mil product and i-th reactant, respectively In the balanced equation.

Class 11 Chemistry Notes For Entropy

In the case of the reaction.

⇒  \(a A+b B \rightarrow c C+a D\Delta S^0=\left(c S_C^0+d S_b^0\right)-\left(a S_A^0+b S_B^0\right)\)

MPBSE Class 11 Chemistry Notes For  Change in entropy of the surroundings in a chemical reaction

The change In entropy of the surroundings in a given process,

⇒ \(\Delta S_{s t u r}=\frac{-q_{s y s}}{T},\) where qÿ is the heat absorbed by the system at 7’K.

In case of chemical reactions occurring at constant pressure \(q_{s y s}=q_P=\) change in enthalpy of the reaction system

⇒\(=\Delta H . \mathrm{So}_1, \Delta \mathrm{S}_{\text {surr }}=-\frac{\Delta H}{T}\)

For exothermic reactions,

⇒ \(\Delta H<0. \text { So, } \Delta S_{\text {surr }}=+v e \text {. }\) I-Ience, the entropy of the surroundings increases In an exothermic reaction.

For endothermic reaction

⇒ \(\Delta H>0 \text {. So, } \Delta S_{\text {surr }}=-v e \text {. }\) Hence, the entropy of the surroundings decreases in an endothermic reaction.

 

MPBSE Class 11 Chemistry Notes For Thermodynamic Process

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Thermodynamic Process

Thermodynamic Process Definition:

A system is said to undergo thermodynamics. A pathway of process: The sequence of system a system process when it undergoes a processis called the pathways of process

Cyclic process Definition

A system is said to haw undergone a cyclic process I if it returns to Its initial state after a series of successive

MPBSE Class 11 Chemistry Notes For Thermodynamics Cyclic Process

Cyclic process Explanation:

Let us consider a process, in which the initial state of a gaseous system is A (Pv Tx). The system returns to its initial state after undergoing consecutive returns to its initial state through three successive operations, it is a cyclic process.

Class 11 Chemistry Notes For Thermodynamic Process

Cyclic process Example:

The following change indicates a cyclic process because 1 mol of water (system) returns to its initial state again through successive changes

MPBSE Class 11 Chemistry Notes For Thermodynamics The Changes In States Functions Are Zero In A Cyclic Process

The changes in state functions are zero in a cyclic process. The value of a state function depends upon the present state of the system. Since the initial and the final states of the system are the same in a cyclic process, the rallies of the state functions in these two states are also the same. So die change in state function (ΔP, ΔV,ΔT,ΔU’, ΔH, etc.) becomes zero for a cyclic process

Isothermal process Definition

If the temperature of a thermodynamic system remains constant throughout a process, then the process Is said to be an Isothermal process,

At the time of conducting this process, the system Is kept lit contact with «a constant temperature heal hath (f.u, thermostat) with a high heat capacity. Such a heat hath Is capable of gaining or losing heat without changing Its temperature.

MPBSE Class 11 Chemistry Notes For Thermodynamic Process

Condition(s) for the isothermal process:

During an Isothermal process, the temperature of the system remains constant. So we can write,dT ‘[system] = constant and d’V[system] or ΔT [system] = 0.

Class 11 Chemistry Notes For Thermodynamic Process

Condition(s) for the isothermal process Example:

The boiling of a liquid at its boiling point Is an isothermal process. This Is because the temperature of the liquid remains constant until the entire liquid converts to vapor. Thus, the boiling ofwater at 100°C and l atm is an isothermal process.

The temperature of the system remains fixed in the isothermal process. U does not mean that heat is not absorbed or liberated by the system during this process.

Isobaric process Definition

A process in which the pressure of the system remains fixed at each step of the process is called an isobaric process.

Condition(s)t for this and the isobaric process:

As the pressure of the system during this process remains constant P{system)=constant and dp (system)or ΔP (system) =0

Isobaric process Example:

The vaporization of any liquid in an open container occurs under atmospheric pressure. If the atmospheric pressure remains fixed, then the process of vaporization is said to be an isobaric process

Isochoric process Definition:

The isochoric process in Which the volume of the system remains constant throughout the process is called an isochoric to process.

Condition(s) for the isochoric process:

The volume of the system remains constant during this process. Hence, V[system] = constant and dV[system] or ΔV [system] =0

Isochoric process  Example: The combustion of n substance In a bomb calorimeter.

For a closed system consisting of an ideal gas. the plots of P vs V for

  1. Isothermic
  2. Isobaric and
  3. Isochoric changes

These are given below:

MPBSE Class 11 Chemistry Notes For Thermodynamics Isothermal Isobaric Isochoric Changes

Class 11 Chemistry Notes For Thermodynamic Process

Adiabatic process Definition

A process in which no exchange of heat takes place between the system and Its surroundings at any stage of the process is called an adiabatic process.

This process requires the system to be covered with a perfect thermal insulator. But in reality, no such material is available and hence the process never becomes one hundred percent adiabatic.

Condition(s) for adiabatic process:

No heat is exchanged between a system and its surroundings In an adiabatic process. So, for such type of process q – 0; where q = heat absorbed or released by the system.

Adiabatic process Example:

The sudden expansion or compression of a gas is considered to be an adiabatic process because when a gas (system) undergoes such a process, it does not get a chance to exchange heat with its surroundings. As a result, the sudden compression of a gas results in an increase in the temperature of the gas, while its sudden expansion leads to a decrease in temperature. For example, when the valve ofa bicycle or car tire is removed, the air coming out ofthe tire undergoes very fast expansion and gets cold.

  1. The temperature of a system does not remain constant in an adiabatic process (except in the case of an adiabatic expansion of an Ideal gas against zero pressure).
  2. For a process involving more than one step, the algebraic sum of heat absorbed or released in different steps may be zero q1 + q2 + q3 + ……………….. = 0, but it does not mean that the process is an adiabatic one.

Reversible process Definition

A process It salt! to be reversible If It Is carried out Infinitesimally slowly so that In each step the thermodynamic equilibrium of the system Is maintained, and any Infinitesimal change In conditions can reverse the process to restore both the system and Its surroundings lo their Initial states.

Class 11 Chemistry Notes For Thermodynamic Process

Reversible process Explanation:

Let us consider that the gas (system) Is enclosed lit a cylinder lilted with a weightless and frictionless piston and the cylinder is kept At a constant temperature hath (surroundings). So, any change occurring In the ire system would be Isothermal. Since the temperature of the system and surroundings tiro the same, the system will remain In thermal equilibrium.

Let the applied external pressure acting on the piston Is the same as that of the gas. So, the system will remain In mechanical equilibrium. Hence, In this condition, the system, the gas Is In a state of thermodynamic equilibrium and pthe roperties of the system remain unchanged

MPBSE Class 11 Chemistry Notes For Thermodynamics Reversible Expansion Of A Gas

Now, if the external pressure is decreased by an infinitesimal amount dP, the volume of the gas will increase very slowly by an infinitesimal amount until the pressure of the gas becomes equal to that of the external pressure.

  • Let the infinitesimal increase of volume = dV. If the external pressure is further decreased by an Infinitesimal amount of dP, the volume of the gas will also increase by an infinitesimal amount of dV.
  • In this way, if the gas is allowed to expand very slowly in an infinite number of steps by decreasing an infinitesimal amount (dP) of the external pressure at each step, then the expansion ofthe gas will reversibly take place.
  • In a step, if the external pressure is increased by an infinitesimal amount (dP), then the volume of the gas will decrease by an infinitesimal amount dV.
  • Hence, by decreasing or increasing the external pressure by an infinitesimal amount, the direction of the process can be reversed.

Class 11 Chemistry Notes For Thermodynamic Process

Characteristics of a reversible process:

  • The driving force of a reversible process is infinite¬ simply greater than the opposing force and by increasing or decreasing the driving force by an infinite¬ amount, the direction of the process can be changed.
  • In this process, the system remains in thermodynamic equilibrium at every intermediate step. This process is extremely slow. From a theoretical point of view, any reversible process requires infinite time for its completion.
  • After the completion a reversible process, if the system is made to return to its initial state by traversing the forward sequence of steps in the reverse order, then both the system and its surroundings are restored to their initial states.
  • The work done by a system in a reversible process is always the maximum
  • The reversible process is extremely slow and infinite time is required to complete the process. A true reversible process is a hypothetical concept. In practice, no process can be carried out reversibly.
  • All processes occurring in nature (i.e., real processes) are irreversible. Nevertheless, the concept of reversibility has immense importance in thermodynamics

Examples of some reversible processes:

1. The vaporization ofa liquid at a particular temperature in a closed container can be considered as a reversible process. Let us consider a certain amount of water is in equilibrium with its vapour at T K temperature in a closed container. Here water and water vapour together constitute a system.

  • If the temperature of the system is increased by an infinitesimal amount of dT, then a very small amount ofwater will vaporize and a new equilibrium will be established.
  • Consequently, the vapor pressure of water will be increased by an infinitesimal amount of DP. If the temperature of the system is decreased by an infinitesimal amount of dT, the same amount of water vapour will condense to establish equilibrium.
  • As a result, the vapour pressure of water is also decreased by an infinitesimal amount of dP. So, by increasing or decreasing the driving force (i.e., by increasing or decreasing temperature) the direction of the process can reversed.
  • Thus, the vaporisation of a liquid at a particular temperature in a closed vessel approximates to a reversible process.

2. Reaction occuring in a galvanic cell is reversible in nature.

  • If an external potential applied between the two electrodes is slightly less in magnitude but opposite in sign than the electromotive force (EMF) of the cell, then the direction of flow of the current and the cell reaction remains unaltered.
  • But, if the externally applied potential slightly exceeds the EMF ofthe cell in magnitude, then the direction of the cell reaction and the direction of current are found to be reversed.
  • Therefore, by slightly increasing or decreasing the external potential (with respect to EMF of the cell), the direction of the cell reaction can be changed.
  • Thus, the reaction occuring in a galvanic cell approximates to a reversible process.

Class 11 Chemistry Notes For Thermodynamic Process

Irreversible process Definition

Aprocess which occurs at a finite rate with the finite ite changes in properties of the system, and at any stage during the process, the system cannot get a chance to remain in thermodynamica equilibrium is called an irreversible process

All natural processes are irreversible in nature.

Irreversible process Explanation:

Let us consider that a certain amount of a gas is enclosed in a cylinder fitted with a weightless and friction¬less piston and the cylinder is kept in a constant temperature heat-bath (thermostat).

  • Therefore ,the temperature of the system gas becomes equal to that of the (system) tsurroundings (thermostat).
  • Let the external pressure applied on the piston (P) and the pressure of the gas are the same
  • Now, if the external pressure is suddenly reduced to P’ , then the gas will expand at a finite rate and this will be irreversible because during expansion the system does not maintain in thermodynamic equilibriuig

MPBSE Class 11 Chemistry Notes For Thermodynamics Irreversible Expansion Of A Gas

Characteristics of an irreversible process:

In an irreversible process there is an appreciable difference between the driving force and the opposing force (actually, the driving force is greater than the opposing force).

  • As a result, such a process takes place at a finite rate, although sometime a very’ slow process may also be irreversible in nature.
  • In an irreversible process, the system does not remain in thermodynamic equilibrium at any stage during the Examples: O The flow of heat from an object of higher process.
  • If an irreversible process is reversed and the system is made to go back to its initial state, then the work done in the backward direction will not be the same as that in the forward direction
  • After the completion of an irreversible process, although the system can be brought back to Its initial state, its surroundings cannot be.
  • Irreversible processes complete in a finite time.

Irreversible process Examples: The flow of heat from an object of higher temperature to an object of lower temperature.

  • The downward flow of water from a mountain.
  • The expansion of a gas against zero pressure.
  • The formation of curd from milk
  • Differences between the reversible and irreversible processes

Class 11 Chemistry Notes For Thermodynamic Process

Differences between the reversible and irreversible processes:

MPBSE Class 11 Chemistry Notes For Thermodynamics Reversible And Irreversible Process

Differences between the reversible and irreversible processes:

MPBSE Class 11 Chemistry Notes For Thermodynamics Isothermal And Anti Biotec