The standard reduction potential for ${\mathrm{Cu}}^{2+}/\mathrm{Cu}$  is +0.34 V. The reduction potential at pH = 14 for the above couple is $[{\mathrm{K}}_{\mathrm{sp}}\left[\mathrm{Cu}{\left(\mathrm{OH}\right)}_2\right]=1.0\times {10}^{-19}]$

$$\begin{gathered} \begin{array}{l}\mathrm{pH}=14\\ \therefore \mathrm{pOH}=0,\left(\text{or}\right)\left[{\mathrm{OH}}^{-}\right]={10}^{-0}=1\\ \text{Therefore }\left[{\mathrm{Cu}}^{2+}\right]=\frac{{\mathrm{K}}_{\mathrm{sp}}}{{\left[{\mathrm{OH}}^{-}\right]}^2}=\frac{1\times {10}^{-19}}{{\left(1\right)}^2}=1\times {10}^{-19}\\ {\mathrm{E}}_{{\mathrm{Cu}}^{2+}/\mathrm{Cu}}={\mathrm{E}}_{{\mathrm{Cu}}^{2+}/\mathrm{Cu}}^{\mathrm{o}}-\frac{0.059}{2}\times 19\end{array} \\ = 0.34-\left[0.03\times 19\right] \\ =-0.22\mathrm{V} \end{gathered}$$