Question

A solution of Ni(NO3)2 is electrolysed between platinum electrodes using a current of 5 amperes for 20 minutes. What mass of Ni is deposited at the cathode?

Answer 1

Given,
Current = 5A
Time = 20 × 60 = 1200 s
∴ Charge = current × time
= 5 × 1200
= 6000 C
According to the reaction,
Ni2+(aq)+2e- $\rightarrow$ Ni(s)
58.7 g
Nickel deposited by 2 × 96487 C = 58.71 g

Therefore, nickel deposited by 6000 C = $\frac{58.71 \times 6000}{2 \times 96487}g$
= 1.825 g

Hence, 1.825 g of nickel will be deposited at the cathode.