Question

A solution of metal salt was electrolyzed with a current of $0.1$ A for $160$ minutes. $Ni$ deposited at cathode was found $0.2950$ g.

What is the charge on metal ion? (Atomic mass of metal is $58.71$)

Answer 1

First calculate the number of moles of electrons passed.
$n=\frac{I\left(A\right)\times t\left(s\right)}{96500}=\frac{0.1\times 160\times 60}{96500}=9.95\times {10}^{-3}$
Now calculate the number of moles of Ni deposited.
$\frac{0.2950}{58.71}=5.025\times {10}^{-3}$.
Now calculate the charge on Ni
$\frac{9.95\times {10}^{-3}}{5.025\times {10}^{-3}}=2$
Hence, the charge on Ni ion is +2.