Question

Three faradays of electricity was passed through an aqueous solution of iron (II) bromide. The weight of iron metal (at. wt.= 56) deposited at the cathode is (in grams):

Answer 1

1 mole of electricity produce 1 equivalent of matter .
so,
mole of electric charge = 3 Faraday
so, no, of equivalent of Fe +2( II) = 3
so, wt of Fe+2 = 3 × equivalent wt of Fe+2
= 3 × 56/2 = 3 × 28 = 84g

Answer 2

The iron metal weight (atomic. Wt = 56) deposited at the cathode is 84 grams.

Explanation:

Faraday is a unit of electric charge.

From the given,

Electricity of three faradays were passed through an aqueous iron (II) bromide solution.

The formation of iron is as follows:

$F e^{2+}+2 e^{-} \rightarrow F e$

From the above reaction, it will states that 2 faradays deposits iron.

Molar mass of Fe = 56 g/mol

2F deposit Fe = 56 g

$\text { For 3F deposit Iron } =\frac{56 \times 3}{2}=84 \ g$