Question

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.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (B)

A process is spontaneous when $\Delta G <0$.
$\Delta G =\Delta H - T \Delta S .$
When $\Delta H <0$, it may lead to negative value for $\Delta G$.
A spontaneous process is an irreversible process and may be reversed by some external agency.
The decrease in enthalpy is a contributory factor for spontaneity.