\(\Delta S=n C_{ v } \ln \frac{T_{2}}{T_{1}}+n R \ln \frac{V_{2}}{V_{1}} \cdots \cdots( I )\)
The volume remains zero for isochoric process.
For diatomic gas;
\(C_{ v }=\frac{5 R}{2}\)
Substitute all the values in the expression \((I)\).
\(\Delta S=1 \times \frac{5 R}{2} \ln \frac{500}{300}\)
\(=\frac{5}{2} \times 8.314 \times 0.5108\)
\(=10.61\,J\)
$2Ag_{(aq)}^ + + c{d_{(s)}} \to cd_{(aq)}^{2 + } + 2A{g_{(s)}}$