Thermodynamics – Multiple Choice Questions

Q1. Which of the following statements is correct about the process of evaporation of water from an open beaker?

1. It is a spontaneous and endothermic process.
2. It is a spontaneous and exothermic process.
3. It is a non-spontaneous and endothermic process.
4. It is a non-spontaneous and exothermic process.

Answer :- (1)

Q2. The absolute entropy of a perfectly crystalline substance is zero at 0 K. The given statement is known as

1. Second law of Thermodynamics
2. Third law of Thermodynamics
3. Law of chemical equilibrium
4. Law of calorimetery

Answer :- (2)

Q3. Which of the following process does NOT occur during a chemical reaction?

1. Rearrangement of atoms
2. Collision between molecules
3. Formation of new atoms
4. Formation of new products from the elements that are not present in the reactants

Answer :- (4)

Q4. For the reaction Hg (l) ———> Hg (g) , the entropy change will have the sign:

1. Negative
2. Positive
3. Both positive and negative
4. None of the above

Answer :- (2)

Q5. Which of the following is NOT a state function?

1. PV
2. q + w
3. q_rev/T
4. q

Answer :- (4)

Q6. The enthalpies of all elements in their standard states are

1. infinite
2. zero
3. negative
4. positive

Answer :- (2)

Q7. The solubility of fluorides is much less as compared to corresponding chlorides

1. because of high ionization energy.
2. because of high lattice enthalpy.
3. because of low ionization energy.
4. because of low lattice enthalpy.

Answer :- (2)

Q8. On which of the following factors the enthalpy change of a reaction is NOT dependent?

1. State of reactants and products
2. Nature of reactants and products
3. Enthalpy of reactants and products
4. Various intermediate reactions

Answer :- (4)

Q9. Which of the following is true about a spontaneous process?

1. Gibbs energy change is 0.
2. Gibbs energy change is less than 0.
3. Gibbs energy change is greater than 0.
4. Spontaneity does not depend on Gibbs energy.

Answer :- (2)

Q10. Which of the following process is NOT included in phase transformation?

1. Vaporization
2. Fusion
3. Ionisation
4. Sublimation

Answer :- (3)

Q11. Which of the following relations is correct for an adiabatic process?

1. ∆U = q
2. P∆V = 0
3. ∆q = 0
4. q = + w

Answer :- (3)

Q12. Which of the following property is NOT an intensive property?

1. Temperature
2. Viscosity
3. Pressure
4. Volume

Answer :- (4)

Q13. The difference between Cp and Cv is equal to

1. 2 kcal mol^-1
2. 1.99 cal
3. 8.314 JK^-1mol^-1
4. 8.314 ergs K^-1 mol^-1

Answer :- ()

Q14. Born-Haber cycle is used to calculate:

1. Lattice enthalpy
2. Enthalpy of formation
3. Enthalpy of sublimation
4. Enthalpy of fusion

Answer :- (1)

Q15. What is the value of the enthalpy of neutralization for all strong acids and bases?

1. -57.1 kJ
2. 57.1 kJ
3. 1 kJ
4. -1 kJ

Answer :- (1)

Q16. What is the change in the entropy of water, When ice melts into water?

1. Entropy of water decreases.
2. Entropy of water increases.
3. Entropy of water becomes zero.
4. Entropy of water remains same.

Answer :- (2)

Q17. Which of the following is a state function?

1. Heat
2. Volume
3. Pressure
4. Internal energy

Answer :- (4)

Q18. On increasing the temperature the entropy of the system

1. Increases
2. Decreases
3. Become zero
4. None of these

Answer :- (1)

Q19. A system absorbs 500 kJ heat and performs 250 kJ work on the surroundings. The increase in internal energy of the system is:

1. 750 kJ
2. 250 kJ
3. 500 kJ
4. 1000 kJ

Answer :- (2)

Q20. What is the enthalpy called when one mole of compound is formed under standard conditions from one mole of its constituent elements in their standard state?

1. Enthalpy of formation
2. Enthalpy of combustion
3. Enthalpy of bond dissociation
4. Enthalpy of phase change

Answer :- ()

Q21. What happens to the ions, when an ionic compound dissolves in a solvent?

1. They leave their ordered position in the crystal lattice and gets hydrated.
2. They leave their ordered position in the crystal lattice and doesn’t hydrate.
3. They doesn’t leave their ordered position in the crystal lattice and gets hydrated.
4. None of the above.

Answer :- (1)

Q22. Evaporation of water is:

1. A process in which no heat changes occur.
2. A process accompanied by chemical reaction.
3. An exothermic change.
4. An endothermic change.

Answer :- (4)

Q23. The process in which no exchange of heat takes place between system and surrounding is known as

1. Isobaric process
2. Adiabatic process
3. Isothermal process
4. Isochoric process

Answer :- (2)

Q24. Enthalpy of hydration of CuSO₄.5H₂O is:

1. positive
2. negative
3. zero
4. not measurable

Answer :- (2)

Q25. For the reaction,

A (g) +2B (g) →  2C (g) +3D(g)

the change of enthalpy at 27^oC is 19 kCal. The Value of ΔE is

1. 21.2 kcal
2. 17.8 kcal
3. 18.4 kcal
4. 20.6 kcal

Answer :- (2)

Q26. What are the units of molar heat capacity?

1. J K^-1 mol^-1
2. J K
3. J K^-1
4. J

Answer :- (1)

Q27. Enthalpy change for a cyclic process is

1. zero
2. positive
3. negative
4. not measurable

Answer :- (1)

Q28. The enthalpies of fusion for all reactions are

1. Positive
2. Negative
3. Zero
4. Depends on the type of substance

Answer :- (1)

Q29. The sum of internal energy and pressure-volume work is defined as

1. Enthalpy
2. Entropy
3. Heat capacity
4. Free energy

Answer :- (1)

Q30. Spontaneous processes proceed:

1. Till equilibrium is achieved.
2. Till conditions are favorable.
3. Till heat is supplied.
4. Till reactant is supplied.

Answer :- (1)

Q31. In the evaporation of water, the entropy

1. decreases
2. increases
3. does not change
4. first increases and then decreases

Answer :- (2)

Q32. What does term specific heat implies?

1. Heat capacity of 1 g of sample
2. Heat capacity of 1 mole of sample
3. Heat capacity of 1Kg of sample
4. Heat capacity of 1000 g of sample

Answer :- (1)

Q33. For a spontaneous chemical process, the free energy change is

1. positive
2. negative
3. zero
4. not measurable

Answer :- (2)

Q34. The increasing order of enthalpy of vaporization of NH₃, PH₃, and AsH₃ is

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

Answer :- (4)

Q35. The internal energy of a system is

1. Kinetic energy only
2. Potential energy only
3. Kinetic as well as potential energy
4. Unpredictable

Answer :- (3)

Q36. In Born-Haber cycle, the sum of the enthalpy changes around a cycle is

1. Zero
2. Constant
3. Negative integer
4. Positive integer

Answer :- (1)

Q37. When there will be increase in the internal energy of a system?

1. If the system gains heat and performs work.
2. If the system gains heat and work performed on the system both are positive.
3. If the system loses heat and performs work.
4. If the system loses heat and work performed on the system both are negative.

Answer :- (2)

Q38. Standard enthalpy of vapourisation ∆_vap H^o for water at 100^oC is 40.66 kJ mol^-1. The internal energy of vaporization of water at 100^oC (in kJmol-1) is:

1. +37.56
2. -43.76
3. +43.76
4.  +40.66

Answer :- (1)

Q39. What is the enthalpy called when one mole of compound reacts completely with excess oxygen under standard conditions?

1. Enthalpy of solution
2. Enthalpy of atomization
3. Lattice enthalpy
4. Enthalpy of combustion

Answer :- (4)

Q40. Heat change of a process in which volume remains constant is given by:

1. ∆H
2. ∆n
3. ∆G
4. ∆U

Answer :- (4)