Question

The signs of $\Delta$H, $\Delta$S and $\Delta$G for a non-spontaneous reaction at all temperatures would be:

• A. +,+,-
• B. +,-,+
• C. -,-,-
• D. +,+, +

Answer 1

The correct option is B +,-,+

Answer:-

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

For a non-spontaneous reaction $\to$

$\Delta G$ must be positive i.e. $\Delta H\&\Delta S$ must be positive and negative respectively.

$\Rightarrow$

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

$\because \Delta S=negative$

$\Delta G=\Delta +H-T(-\Delta S)$

$\Rightarrow \Delta G=\Delta H+T\Delta S=positive$

Hence, B is the correct answer.