Question

When electricity is passed through a solution of AlCl₃, 13.5 g of Al is discharged, the amount of charge passed is ______.

Options

• 1.5 F

• 0.5 F

• 1.0 F

• 2.0 F

Answer 1

When electricity is passed through a solution of AlCl₃, 13.5 g of Al is discharged, the amount of charge passed is 1.5 F.

Explanation:

Aluminium is deposited from aluminium chloride (AlCl₃) according to the half-cell reaction:

\[\ce{Al^3+ + 3e- -> Al}\]

Equivalent mass of Al = `27/3` = 9

Mass deposited = 13.5 g

Now using Faraday’s law,

Charge = `"Mass"/"Equivalent mass"`

= `13.5/9`

= 1.5 F