Question

How many Faradays of electricity is required to produce 4.8 g of Mg at cathode in the electrolysis of molten MgCl₂?
(Molar mass of Mg = 24 g/mol)

Options

• 4 F

• 0.4 F

• 1 F

• 10 F

Answer 1

0.4 F

Explanation:

Electrode reaction:

\[\ce{Mg^{2+} + 2e- -> Mg(s)}\]

To produce 24 g of Mg from molten MgCI₂, electricity required = 2 F

To produce 4.8 g Mg from MgCl₂, electricity required

`= ((2"F") xx 4.8 "g")/(24 "g")` = 0.4 F