Question

How many coulombs of electricity are required to produce 40g of Al from Al 3+ solution

Answer 1

The Faraday constant is given by :

Faraday constant = 96500 Coulombs per mol

It takes 3 electrons to deposit 1 mole of Aluminium .

This is written as follows:

Al³⁺ + 3e⁻ ........>  Al(s)

Therefore :

1 mole of Aluminium = 96500 × 3 = 289500 Coulombs

The molar mass of Aluminium is 27g per mole

The moles of Aluminium in 40 g is given by :

40/27 = 1.48 moles

The Coulombs required is thus given by :

1.48 × 289500 = 428460 Coulombs.

= 4.2846 × 10⁶