A solution of `Ni(NO_3)_2` is electrolysed between platinum electrodes using a current of 0.5 ampere for 20 minutes. What mass of Ni is deposited at the cathode ?

Explanation

Quantity of electricity passed `=(5A) xx (20 xx 60 s) = 6000 C`
`Ni^(2+) + 2e^(-) to Ni`
Thus, 2F, i.e. `2 xx 96500 C` will deposit = 1mole, i.e. 58.7 g of Ni
`therefore 6000 C` will deposit `=58.7/(2 xx 96500 ) xx 6000 g = 1.825 g` of Ni.