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Class 11 chemistry MCQ Question of Thermodynamics with Answers?

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Firstly, explaining Thermodynamics here: - Thermodynamics is the study of the transformations of energy. The chemical energy present in a particle is delivered in a different reaction. The laws of thermodynamics manage a naturally visible composition present in balance or changing starting with one condition of harmony then onto the next.

Class 11 Chemistry MCQ Questions of Thermodynamics with Answers for a speedy revision of the Chapter in this manner assisting you with improving Knowledge about the subjects. Solving the Class 11 Chemistry MCQ Questions of Thermodynamics with Answers can be of outrageous assistance as you will know about every one of the ideas and Concepts. These MCQ Questions are prepared by our subjects experts based on syllabus and exam pattern. 

Learn the MCQ Question for Class 11 Chemistry cross-check your answers with definite Solutions and furthermore Check your preparation for examinations.

Practice MCQ Questions for class 11 Chemistry Chapter-Wise

1. Third law of thermodynamics provides a method to evaluate which property?

(a) Absolute Energy
(b) Absolute Enthalpy
(c) Absolute Entropy
(d) Absolute Free Energy

2. One mole of which of the following has the highest entropy?

(a) Liquid Nitrogen
(b) Hydrogen Gas
(c) Mercury
(d) Diamond

3. The species which by definition has ZERO standard molar enthalpy of formation at 298 K is

(a) Br2(g)
(b) Cl2(g)
(c) H2O(g)
(d) CH4(g)  

4.  In a reversible process the system absorbs 600 kJ heat and performs 250 kJ work on the surroundings. What is the increase in the internal energy of the system?

(a) 850 kJ
(b) 600 kJ
(c) 350 kJ
(d) 250 kJ

5. Which of the following is true for the reaction? H2O(l) ⇔H2O(g) at 100° C and 1 atm pressure

(a) ∆S = 0
(b) ∆H = T ∆S
(c) ∆H = ∆U
(d) ∆H = 0

6. A system absorb 10 kJ of heat at constant volume and its temperature rises from 270 C to 370 C. The value of ∆ U is

(a) 100 kJ
(b) 10 kJ
(c) 0 kJ
(d) 1 kJ

7. In which of the following process, a maximum increase in entropy is observed?

(a) Dissolution of Salt in Water
(b) Condensation of Water
(c) Sublimation of Naphthalene
(d) Melting of Ice

8. Which thermodynamic function accounts automatically for enthalpy and entropy both?

(a) Helmholtz Free Energy (A)
(b) Internal Energy (E)
(c) Work Function
(d) Gibbs Free Energy

9. Based on the first law of thermodynamics, which one of the following is correct?

(a) For an isothermal process, q = +w
(b) For an isochoric process, ΔU = -q
(c) For an adiabatic process, ΔU = -w
(d) For a cyclic process, q = -w

10. The temperature of the system decreases in an .........

(a) Adiabatic Compression
(b) Isothermal Expansion
(c) Isothermal Compression
(d) Adiabatic Expansion

11.  Which of the following salts will have maximum cooling effect when 0.5 mole of the salt is dissolved in same amount of water. Integral heat of solution at 298 K is given for each salt?

(a) KNO3 (∆H = 35.4 kJ mol-1)
(b) NaCl (∆H = 5.35 kJ mol-1)
(c) HBr (∆H = -83.3 kJ mol-1)
(d) KOH ( ∆H = -55.6 kJ mol-1)

12. Thermodynamics is not concerned about

(a) the rate at which a reaction proceeds
(b) the feasibility of a chemical reaction
(c) the extent to which a chemical reaction proceeds
(d) energy changes involved in a chemical reaction

13. Which of the following is closed system?

(a) Pressure cooker
(b) Rocket engine during propulsion
(c) Tea placed in a steel kettle
(d) Jet engine

14. Assertion: The part of the universe chosen for study of energy changes is called system.

Reason: whereas the rest of the universe is called surroundings.

(a) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
(b) Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
(c) Assertion is correct but Reason is incorrect
(d) Both Assertion and Reason are incorrect

15. When the bond being formed are more than those being broken in a chemical reaction, then the ΔH will be

(a) Positive
(b) Negative
(c) Zero
(d) Both a and c

16. Two cylinders A and B of equal capacity are connected to each other via a stop cock. A contains an ideal gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stop cock is suddenly opened. The process is : 

(a) adiabatic 
(b) isochoric 
(c) isobaric 
(d) isothermal

17. The efficiency of a Carnot engine depends upon:

(a) the temperature of the sink only
(b) the temperatures of the source and sink
(c) the volume of the cylinder of the engine
(d) the temperature of the source only

18. A gas is compressed isothermally to half its initial volume. The same gas is compressed separately through an adiabatic process until its volume is again reduced to half. Then -

(a) compressing the gas through adiabatic process will require more work to be done
(b) compressing the gas isothermally or adiabatically will require the  same amount work
(c) which of the case (whether compression through isothermal or through adiabatic process) requires more work will depend upon the atomicity of the gas
(d) compressing the gas isothermally will require more work to be done

19. An ideal gas is compressed to half its initial volume by means of several process. Which of the process results in the maximum work done on the gas?

(a) Adiabatic
(b) Isobaric
(c) Isochoric
(d) Isothermal

20. If ΔU and ΔW represent the increase in internal energy and work done by the system respectively in a thermodynamical process, which of the following is true?

(a) ΔU = −ΔW,  in a adiabatic process
(b) ΔU = ΔW,  in a isothermal process
(c) ΔU = ΔW,  in a adiabatic process
(d) ΔU = −ΔW,  in a isothermal process

21. The internal energy change in a system that has absorbed 2 kcal of heat and done 500 J of work is 

(a) 8900 J
(b) 6400 J
(c) 5400 J
(d) 7900 J

22. At absolute zero, the entropy of a perfect crystal is zero. This is........... of thermodynamics.

(a) the first law
(b) second law
(c) third law            
(d) none of these

23. Entropy decreases during:

(a) crystallization of sucrose from solution
(b) rusting of iron
(c) melting of ice
(d) vaporization of camphor

24. During the adiabatic process,

(a) pressure is maintained constant
(b) gas is isothermally expanded
(c) there is a perssure volume work
(d) The system changes heat with surrounding

25. Warming ammonium chloride with sodium hydroxide in a test tube is an example of:

(a) closed system
(b) Isolated system
(c) open system
(d) None of these

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Answer:

1. Answer: (c) Absolute Entropy

Explanation: The Third Law of Thermodynamics is concerned with the limiting behavior of systems as the temperature approaches absolute zero. Most thermodynamics calculations use only entropy differences, so the zero point of the entropy scale is often not important. However, the Third Law tells us about the completeness as it describes the condition of zero entropy.

2. Answer: (b) Hydrogen Gas

Explanation: Entropy is the measure of degree of disorder (or randomness) of a system. The greater the disorder in a system, the higher is the entropy. Hence, entropy is highest for hydrogen gas.

3. Answer: (b) Cl2(g)

Explanation: Elements in its standard state have zero enthalpy of formation. Cl2 is gas at room temperature, therefore ΔH°f of Cl2(g) is zero. 

4. Answer: (c) 350 kJ

Explanation: ∆E = q + w 

= 600 – 250

∆E = 350 J  

5. Answer: (b) ∆H = T ∆S 

Explanation: ∆ G = 0 = ∆ H – T ∆ S

Or T∆ S = ∆H

6. Answer: (b) 10 kJ

Explanation: At constant volume w = 0

Therefore, ∆ U = q = 10 kJ

7. Answer: (c) Sublimation of Naphthalene

Explanation: The order of entropy in solid, liquid and gas is gas > liquid > solid. Hence, in sublimation of naphthalene, maximum increase in entropy is observed.

8. Answer: (d) Gibbs Free Energy

Explanation: Gibbs free energy combines the effect of both enthalpy and entropy. The change in free energy (ΔG) is equal to the sum of the change of enthalpy (∆H) minus the product of the temperature and the change of entropy (∆S) of the system. ∆G = ∆H – T∆S.

9. Answer: (d) For a cyclic process, q = -w

Explanation: According to first law of thermodynamics,

ΔU = Q+W

For cyclic process, change in internal energy =0

∴Q =−W

10. Answer: (a) Adiabatic Compression

Explanation: In adiabatic expansion work is done by the system so it will lose heat to the surrounding. Thus, temperature of the system decreases.

11. Answer: (a) KNO3 (∆H = 35.4 kJ mol-1)

Explanation: A salt with maximum ΔHsolution will cause maximum cooling.

12. Answer: (a) the rate at which a reaction proceeds

Explanation: Thermodynamics is not concerned about how and at what rate chemical reactions are carried out, but is based on initial and final states of a system undergoing the change.

13. Answer: (a) Pressure cooker

Explanation: For example, the contents of a pressure cooker on a stove with its lid tightly closed and the whistle in position, is a closed system as no mass can enter or leave the pressure cooker, but heat can be transferred to it.

14. Answer: (b) Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

Explanation: The system is the part of the universe being studied, while the surroundings are the rest of the universe that interacts with the system.

15. Answer: (b) Negative

Explanation: If less energy is needed to break up the reactant molecules into their constituent atoms than is released when these atoms are reconstituted into product molecules, then the reaction will be exothermic.

16. Answer: (a) adiabatic 

Explanation: The entire system is completely insulated and the free expansion of the gas will take place, the temperature of the gas will remain constant. So the process will be adiabatic.

17. Answer: (b) the temperatures of the source and sink

Explanation: The efficiency of a Carnot engine depends on the temperatures of the hot and cold reservoirs is the ratio of the work done by the engine to the heat drawn out of the hot reservoir. Carnot's theorem is a consequence of the second law of thermodynamics.

18. Answer: (a) compressing the gas through adiabatic process will require more work to be done

Explanation: Wext = negative of area with volume-axis

W(adiabatic) > W(isothermal)

19. Answer: (a) Adiabatic

Explanation: The P -V diagram of an ideal gas compressed from its initial volume V0  to V0/2 by several processes is shown in the figure.

Work done on the gas: Area under P-V curve As area under the P-V curve is maximum for adiabatic process, so work done on the gas is maximum for adiabatic process.

20. Answer: (a) ΔU = −ΔW,  in a adiabatic process

Explanation: According to first law of thermodynamics

ΔQ = ΔU + W

For an adiabatic process, ΔQ = 0

∴ΔU = −W

21. Answer: (d) 7900

Explanation: dU = Q − W

= 8400 − 500

= 7900J

22. Answer: (c)  third law  

Explanation: The third law of thermodynamics states that "The entropy of a perfectly crystalline substance at zero K or absolute zero is taken to be zero".

23. Answer: (a) crystallization of sucrose from solution

Explanation: Entropy is a measure of randomness during the crystallisation of sucrose solution liquid state is changing into solid state hence entropy decreases.

24. Answer: (c) there is a perssure volume work

Explanation: dq=0, for adiabatic process, which means perfect heat insulation.

25. Answer: (c) open system

Explanation: When we are warming ammonium chloride with sodium hydroxide in a test tube, there is exchange of heat as well as mass between system and surrounding. Mass is transferred from the open end of the test tube due to evaporation. Also heat is being exchanged through the walls of test tube.

Click here to practice MCQ Questions for Thermodynamics class 11

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