Question

In which of the following cells $E_{\text {cell }}=E^{\circ}$ cell ?

• A. $Cu (s)\left| Cu ^{2+}(0.01\, M )\right|\left| Ag ^{+}(0.1\, M )\right| Ag(s)$
• B. $Pt \left( H _{2}\right)| pH =1|\left| Zn ^{2+}(0.01\, M )\right| Zn (s)$
• C. $Pt\left( H _{2}\right)| pH =1|\left| Zn ^{2+}(1\, M )\right| Zn (s)$
• D. $Pt\left( H _{2}\right)\left| H ^{+}=0.01\, M \right|\left| Zn ^{2+}(0.01\, M )\right| Zn (s)$

Answer 1

Answer: (A), (B)

From Nernst equation,
$E_{\text {cell }}=E_{\text {cell }}^{\circ}-\frac{0.0591}{n F} \log Q$.
If $Q=1, \log Q=0$ so, $E_{\text {cell }}=E_{\text {cell }}^{\circ}$
This condition is found in (a) and (b).