Question

Read the following statements regarding spontaneity of a process and mark the appropriate choice.
(i) When enthalpy factor is absent then randomness factor decides spontaneity of a process.
(ii) When randomness factor is absent then enthalpy factor decides spontaneity of a process.
(iii) When both the factors take place simultaneously, the magnitude of both of factors decide spontaneity of a process.

• A. Statements $(i)$ and $(ii)$ are correct and $(iii)$ is incorrect
• B. Statement $(iii)$ is correct, $(i)$ and $(ii)$ are incorrect
• C. Statements $(i)$, $(ii)$ and $(iii)$ are correct
• D. Statements $(i)$, $(ii)$ and $(iii)$ are incorrect

Answer 1

Answer: (C)

We know,
$\Delta G=\Delta H-T\Delta S$
Now,
1. $\Delta G=\Delta H$ when $\Delta S=0$.
2. $\Delta G=T\Delta S$ when $\Delta H=0$
3. $\Delta G=\Delta H-T\Delta S$ when $\Delta H\ne 0\ne \Delta S$