Answer to Question #165518 in Chemistry for Das

Question

In the electrolysis of melted MgCl₂, an electric current of 52115 Coulomb is used, the mass of Mg produced is ...

Answer 1

Solution:

Electrolysis of the molten MgCl₂:

Mg²⁺ + 2e^- → Mg (at the (-)cathode).

2Cl^- - 2e^- → Cl₂ (at the (+)anode).

The overall reaction is:

MgCl_2(l) → Mg_(s) +   Cl_2(g)

By Faraday's first law

w = z × Q

where:

z = Electrochemical equivalent = Atomic mass / (Electrons × 96500)

Q = Coulombs of electricity

Hence,

Mass of Mg = (M × Q) / (n_e × F)

Mass of Mg = (24 × 52115) / (2 × 96500) = 6.48 g

Mass of Mg = 6.48 g

Answer: 6.48 grams of Mg is produced.