Question

How much charge is necessary to liberate one equivalent of a substance and why? Calculate the value of this charge.

Answer 1

According to Faraday’s First Law of Electrolysis, the amount of a substance deposited or liberated at an electrode is directly proportional to the quantity of electricity (charge) passed through the electrolyte. To liberate one equivalent of a substance, one mole of electrons is required. One equivalent of a substance corresponds to one mole of electrons.

The charge on one electron is:

e = 1.602 × 10⁻¹⁹ C

The number of electrons in one mole = Avogadro’s number:

N_A = 6.022 × 10²³

Charge (Q) = N_A​ × e

= (6.022 × 10²³) × (1.602 × 10⁻¹⁹)C

= 96,485 C