Question

Purification of nickel can be achieved by electrorefining nickel from an impure nickel anode onto a pure nickel cathode in an electrolytic cell. How many hours will it take to plate 18.0 kg of nickel onto the cathode if the current passed through the cell is held constant at 31.0 A ? Assume the nickel in the electrolytic solution is present as Ni2+ .

Answer 1

Answer: 530 hours

Explanation:

The reduction of Nickel ions to nickel is shown as:

$Ni^{2+}+2e^-\rightarrow Ni$

$96500\times 2=193000Coloumb$ of electricity deposits 1 mole of Nickel

1 mole of Nickel weighs = 58.7 g

Given quantity = 18.0 kg = 18000 g  (1kg=1000g)

58.7 g of Nickel is deposited by 193000 C of electricity

18000 g of Nickel is deposited by = $\frac{193000}{58.7}\times 18000=59182282.8C$ of electricity

$Q=I\times t$

where Q= quantity of electricity in coloumbs  = 59182282.8C

I = current in amperes = 31.0 A

t= time in seconds = ?

$59182282.8C=31.0A\times t$

$t=1909105.9sec$

(1h=3600 sec)

$t=530hours$

Thus 530 hours are required to plate 18.0 kg of nickel onto the cathode if the current passed through the cell is held constant at 31.0 A