Question

How long a current of $3$ ampere has to be passed through a solution of $AgN{O}_3$ to coat a metal surface of $80c{n}^2$ with a thickness of $0.005mm$? Density of $Ag$ is $10.5gc{m}^{-3}$.

Answer 1

The electrolysis of $Ni(N{O}_3{)}_2$ in presence of $Ni$ electrode will bring in following changes:
At anode : $Ni\to N{i}^{2+}+2e$
At cathode : $N{i}^{2+}+2e\to Ni$
Eq. of $N{i}^{2+}$ formed = Eq. of $N{i}^{2+}$ lost
Thus, there will be no change in conc. of $Ni(N{O}_3{)}_2$ solution during electrolysis.
It will remain 2 M.