For the calomel half-cell, `Hg, Hg_(2)Cl_(2)|Cl^(-)(aq)` values of electrode potentials are plotted at different log `[Cl^(-)]`. Variation is represented by

Options

A.
B.
C.
D.

Answer

A

Explanation

The half cell reaction of the calomel electrode (written as reduction reaction) is
`Hg_(2)Cl_(2)(s)+2e^(-)to2Hg(l)+2Cl^(-)(aq)`
`E=E^(@)-(0.0591)/(2)log[Cl^(-)]^(2)`
or `E=E^(@)-0.0591log[Cl^(-)]`
Thus, plot of E vs log `[Cl^(-)]` is linear with a negative slope (i.e., E decreases linearly with log `[Cl^(-)]`)