Which of the following statement is incorrect for dry cell ?

$\text{ Anode }\mathrm{Zn}\left(\mathrm{s}\right)⟶{\mathrm{Zn}}^{2+}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-}$
$\text{ Cathode }{\text{MnO}}_2+{\mathrm{NH}}_4^{+}+{\mathrm{e}}^{-}⟶\mathrm{MnO}\left(\mathrm{OH}\right)+{\mathrm{NH}}_3$
At cathode manganese is reduced from +4 oxidation state to +3 oxidation state. Ammonia produced in reaction from complex with Zn²⁺ to give ${\left[\mathrm{Zn}{\left({\mathrm{NH}}_2\right)}_4\right]}^{2+}$. The cell has potential of 1.5 V.