3 RBTS PAPER
162645
Which of the following reaction is never expected to be spontaneous :-
1 \(2 \mathrm{O}_3(\mathrm{~g}) \rightarrow 3 \mathrm{O}_2(\mathrm{~g}) \quad \Delta \mathrm{H}=-\mathrm{ve}, \Delta \mathrm{S}=+\mathrm{ve}\)
2 \(\mathrm{Mg}(\mathrm{s})+\mathrm{H}_2(\mathrm{~g}) \rightarrow \mathrm{MgH}_2 \quad \Delta \mathrm{H}=-\mathrm{ve}, \Delta \mathrm{S}=-\mathrm{ve}\)
3 \(\mathrm{Br}_2(\mathrm{I}) \rightarrow \mathrm{Br}_2(\mathrm{~g}) \quad \Delta \mathrm{H}=+\mathrm{ve}, \Delta \mathrm{S}=+\mathrm{ve}\)
4 \(2 \mathrm{Ag}(\mathrm{s})+3 \mathrm{~N}_2(\mathrm{~g}) \rightarrow 2 \mathrm{AgN}_3 \Delta \mathrm{H}=+\mathrm{ve}, \Delta \mathrm{S}=-\mathrm{ve}\)
Explanation:
\( \Delta \mathrm{G}=\Delta \mathrm{H}-\mathrm{T} \Delta \mathrm{S} \)
If \(\Delta \mathrm{H}=+\mathrm{ve}, \Delta \mathrm{S}=-\mathrm{ve}\)
\(\Delta \mathrm{G}=+\mathrm{ve}\) means non-spontaneous in nature