Question

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

• A. can be negative but numerically larger than x/298
• B. can be negative but numerically smaller than x/298
• C. cannot be negative
• D. cannot be positive

Answer 1

The correct option is B can be negative but numerically smaller than x/298

It is because of the fact that for spontaneity, the value of $△G=(△H-T△S)$ should be < 0.
If $△S$ is - ve, the value of $T△S$ has to be less than $△H$ or the value of $△S$ has to be less than $\frac{△H}{T}$ , i.e., $\frac{x}{298}$