Question

Electrode potential of the half cell $Pt\left(s\right)|Hg\left(l\right)|{Hg}_2{Cl}_2\left(s\right)|{Cl}^{-}\left(aq\right)$ can be increased by:

• A. increasing $\left[{Cl}^{-}\right]$
• B. decreasing $\left[{Cl}^{-}\right]$
• C. increasing ${Hg}_2{Cl}_2\left(s\right)$
• D. decreasing $Hg\left(l\right)$

Answer 1

The correct option is A increasing $\left[{Cl}^{-}\right]$

We know that $E_{cell}$ is given by the equation,

$E_{cell}=E_{cell}^0-\frac{0.059}{n}log\left(K\right)$

where, $K=\frac{[Products{]}^b}{[Reactants{]}^a}$ where a and b are stoichiometric co-efficients.

Here,$K=\frac{[Cl{]}^{-}}{\left[Hg\right]}$

On substituting the value of K in the equation and we can see that if we decreasing the value of $[Cl{]}^{-}$ electrode potential increases.