Question

Calomel electrode is reversible with respect to:

• A. H${}^{+}$ ions
• B. Hg${}_2^{2+}$ ions
• C. Cl${}^{-}$ ions
• D. None of these

Answer 1

The correct option is C Cl${}^{-}$ ions

Calomel Electrode :

$Hg\left(l\right)/H{g}_{2}C{l}_2\left(s\right)/C{l}^{-}\left(aq\right)$

It is prepared by a $Pt$ wire in contact with a paste of $Hg$ and $H{g}_{2}C{I}_2$ present in a $KCl$ solution.

reaction $\frac{1}{2}H{g}_{2}C{l}_2\left(s\right)+e^{-}\to Hg\left(l\right)+C{l}^{-}$

$E=E^{\circ }-0.0591log\left[C{l}^{-}\right]$