Faraday discovered that the mass of substance discharged is proportional to the quantity of current passing it.
1 Coulomb = Current x time C – quantity of electricity
C = It t – time in seconds I – current in amperes
1 mole of electron has a charge of 96, 500C so;
M+ + e → M requires 96, 500C
M2+ + 2e → M requires 2 x 96, 500C
E.g. What mas of magnesium is deposited at the cathode by passing 2A through molten MgCl2 for 30 min?
- C = It
- To find mass Mg2+ + 2e → Mg requires …….
- 1mol Mg = 24g
Applications of Electrolysis
- Electrolysis is used to produce sodium Na.