A solution is electrolysed between platinum electrodes using a current of 5 A for 20 min. What mass of Ni is deposited at the cathode?
Here, current = 5 A, time = 20 min
Quantity of electricity passed will be
Q = it= 5 Ax20x 60s = 6000 C
Electrolysis of gives
${{Ni}^{2+}}$+ ${{2e}^{-}}$ -----> Ni (Atomic mass of Ni = 58.7)
Therefore, electricity required for 1 mole, i.e. 58.7 gNi is 2 F= 2 x 96500 C
2 x 96500 C deposit Ni = 58.7 g
.’. 6000 C will deposit Ni = 58.7 x 6000 /2 x 96500g = 1.825 g