Question

The occurrence of the reaction is impossible if

• A. $ \Delta H $ is $ +\,ve;\Delta S $ is also $ +\,ve $
• B. $ \Delta H $ is $ ~-ve;\text{ }\Delta S $ is also $ -ve $
• C. $ \Delta H $ is $ -ve;\Delta \,S $ is $ +\,ve $
• D. $ \Delta H $ is $ +\,ve;\Delta S $ is $ -ve $

Answer 1

Answer: (D)

When $\Delta G$ is $+$ ve, then reaction is not possible.
$\Delta G=\Delta H-T . \Delta S$ If $\Delta H=+v e$ and $\Delta S=+v e$, then $\Delta G=+v e$
only when $\Delta H>T . \Delta S$ but if $\Delta H=+v e$ and $\Delta S=-v e$, then $\Delta G=+v e$.