Verification of Faraday’s Second law of electrolysis
Faraday’s second law of electrolysis states that, when the same quantity of electricity is passed through several electrolytes, the mass of the substances deposited are proportional to their respective chemical equivalent or equivalent weight.
Two electrolytic cells containing different electrolytes, CuSO4 solution and AgNO3 solution are connected in series with a battery, a rheostat and an ammeter (Figure). Copper electrodes are inserted in CuSO4 and silver electrodes are inserted in AgNO3.
The cathodes are cleaned, dried, weighed and then inserted in the respective cells. The current is passed for some time. Then the cathodes are taken out, washed, dried and weighed. Hence the masses of copper and silver deposited are found as m1 and m2.
It is found that
m1/m2 = E1/E2
where E1 and E2 are the chemical equivalents of copper and silver respectively.
m α E
Thus, the second law is verified.