Question

For a process to be spontaneous at all conditions of temperature, which of the following is correct?

• A. $\Delta S$ positive and $\Delta H$ positive
• B. $\Delta S$ positive and $\Delta H$ negative
• C. $\Delta S$ negative and $\Delta H$ positive
• D. $\Delta S$ negative and $\Delta H$ negative

Answer 1

Answer: (B)

$\Delta S$ positive and $\Delta H$ negative

As $\Delta G=\Delta H-T\Delta S$, for $\Delta H$ negative and $\Delta S$ positive, $\Delta G$ will always be negative.

$\Delta G$ negative implies that the process will be spontaneous.