Three Faradays of electricity was passed through an aqueous solution of iron (II) bromide. The mass of iron metal (atomic mass 56) deposited at the cathode is

56 g 84 g 112 g 168 g

84 g

The cell reaction can be written as \(Fe^{2+} + 2e^− \rightarrow Fe\) ∴ Mass of iron deposited for 1F charge = \(\frac{56}{2}\) g ∴ Mass of iron deposited for 3F charge = \(\frac{56}{2} × 3 \frac{168}{2} = 84\) g