# $Cu5O_4$ solution is not stable in $Zn$ container because of

$\begin{array}{1 1}(a)\;\text{because of formation of}(Cu)_25O_4\\(b)\;\text{because of formation of Cu}\\(c)\;\text{because of formation Cu-Zn alloy}\\(d)\;\text{because of formation of }Zn5O_3\end{array}$

$E^o_{Cu^{+2}/Cu} > E^o_{Zn^{+2}/Zn}$
$Zn(s) +Cu^{+2}(aq)\rightarrow Zn^{+2}(aq)+Cu$
Hence (b) is the correct answer.