Assertion and Reason Questions for Class 11 Chemistry Chapter 6 Thermodynamics
(a) Assertion and reason both are correct statements and reason is correct explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.
Q.1. Assertion : Enthalpy of formation of graphite is zero but of diamond it is not zero.
Reason : Enthalpy of formation of the most stable allotrope is taken as zero.
AnswerAnswer:(a) : Graphite is the most stable form.
Q.2. Assertion : Heat of neutralisation for both H2SO4 and HCl with NaOH is 53.7 kJ mol –1.
Reason : Both HCl and H2SO4 are strong acids.
Q.3. Assertion : Some salts are sparingly soluble in water at room temperature.
Reason : The entropy increases on dissolving the salts.
Q.4. Assertion : Spontaneous process is an irreversible process and may be reversed by some external agency.
Reason : Decrease in enthalpy is a contributory factor for spontaneity.
Q.5. Assertion : Decrease in free energy causes spontaneous reaction.
Reason : Spontaneous reactions are invariable exothermic reactions.
AnswerAnswer:(c) : Exothermic reactions are spontaneous at low temperature but becomes non-spontaneous at high temperature.
Q.6. Assertion : The heat absorbed during the isothermal expansion of an ideal gas against vaccum is zero.
Reason : The volume occupied by the molecules of an ideal gas is zero.
Q.7. Assertion : U is a state function.
Reason : T is an intensive property.
Q.8. Assertion : Entropy of system increases for a spontaneous reaction.
Reason : Enthalpy of reaction always decreases for spontaneous reaction.
AnswerAnswer:(a) : ∆S is +ve and ∆H is –ve for a spontaneous reaction at all temperatures.
Q.9. Assertion : Sublimation of the solid is nonspontaneous.
Reason : Sublimation is endothermic process.
AnswerAnswer:(d) : Sublimation of the solid is spontaneous due to increase in entropy.
Q.10. Assertion : The sum of q + w is a state function.
Reason : Work and heat are state functions.