Question

A reaction is spontaneous at all temperatures when

• A. $\Delta H$ is -ve and $\Delta S$ is +ve
• B. $\Delta H$ is +ve and $\Delta S$ is -ve
• C. both $\Delta H$ and $\Delta S$ are -ve
• D. both $\Delta H$ and $\Delta S$ are +ve

Answer 1

Answer: (A)

$\Delta H$ is -ve and $\Delta S$ is +ve

Answer 2

$\Delta G = \Delta H - T \Delta S$

Reaction is spontaneous if $\Delta G$ is -ve and $\Delta G$ will always be - ve when $\Delta H$ is -ve and $\Delta S$ is +ve