For the oxidation of $0.2 \mathrm{M} \mathrm{FeSO}_4$ solution 0.965 amperes current is passed through it…

For the oxidation of $0.2 \mathrm{M} \mathrm{FeSO}_4$ solution 0.965 amperes current is passed through it for 1 hour. The volume of the solution that is oxidised in $\mathrm{mL}$ is
  1. 70
  2. 80
  3. 60
  4. 90

Solution

The equation is $ \mathrm{Fe}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Fe} $ 1 mole is deposited by $2 \times 96500^{\circ} \mathrm{C}=193000^{\circ} \mathrm{C}$ The charged supplied $=0.965 \times 60 \times 60$ $ =3474 \mathrm{C} \quad(\because Q=i \times t) $ Number of moles deposited by this charge $ \begin{aligned} & =\frac{3474}{193000}=0.018 \mathrm{~mol} \\ & \text { Molarity }=\frac{\text { Number of moles } \times 1000}{\text { Volume in } \mathrm{mL}} \\ & \text { Volume }(\text { in } \mathrm{mL})=\frac{\text { Number of moles } \times 1000}{M(\text { molarity })} \\ & =\frac{0.018 \times 1000}{0.2}=90 \mathrm{~mL} \\ & \end{aligned} $

Asked in: AP EAMCET 2018 (23 Apr Shift 1)

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