Assume that $C{u}^{2+}(0\mathrm{.}01M)$ and $S{n}^{2+}(0\mathrm{.}01M)$ are dissolved in aqueous solutions of $pH=0.$

$($a$)$ Calculate the potential at which the plating of $Cu$ and $Sn$ can start when the potential of an

inert electrode $($Pt$)$ is gradually changed from $1\mathrm{.}6V($vs$.$ NHE$)$ to the negative values. $(5$pt$)$

$C{u}^{2+}+2e=Cu,E=0\mathrm{.}34V(vs.$ NHE$)$

$S{n}^{2+}+2e=Sn,E=-0\mathrm{.}14V(vs.$ NHE$)$

$($b$)$ In contrast to $Cu,$ the $pH$ of aqueous solution should be kept high enough in the industrial

plating process of $Sn.$ Describe the reason why it is$.(10$pt$)$