Question

The enthalpy change for a given reaction at $298K$ is $-xJ{mol}^{-1}$(x being positive) If the reaction occurs spontaneously at $298K$, the entropy change at that temperature :

• A. Can be negative but numerically larger than $\frac{x}{298}$
• B. Can be negative but numerically smaller than $\frac{x}{298}$
• C. Cannot be negative
• D. Cannot be positive

Answer 1

Answer: (B)

Can be negative but numerically smaller than $\frac{x}{298}$

For spontaneous reaction $\Delta G$ should be negative. we know that $\Delta G$=$\Delta H-T\Delta S$.

So $\Delta H<T\Delta S$ for a spontaneous reaction.