Chemistry 9701 · AS & A Level · Electrochemistry

Electrochemistry — practice question

Use data from Table 3.1 to answer some parts of this question.
(a(i))[1]

Describe the standard conditions applied to the $\text{Sn}^{4+}/\text{Sn}^{2+}$ half-cell.

(a(ii))[3]

Complete the diagram below to show experimentally how $E^\circ(\text{Sn}^{4+}/\text{Sn}^{2+})$ may be measured. Your diagram must be fully labelled so that every apparatus item and substance is identified.

(a(iii))[2]

Equal volumes of $1.0\,\text{mol dm}^{-3}\,\text{Sn}^{2+}(aq)$ and $1.0\,\text{mol dm}^{-3}\,\text{Cl}^-(aq)$ are mixed. Use relevant $E^\circ$ values to explain whether a reaction takes place between these ions.

(a(iv))[2]

Equal volumes of $1.0\,\text{mol dm}^{-3}$ of $\text{Sn}^{2+}(aq)$ and acidified $1.0\,\text{mol dm}^{-3}\,\text{VO}_2^+(aq)$ are mixed. Write an equation for the reaction occurring in the final mixture.

(b)[2]

A solution of $\text{SnCl}_2(aq)$ is electrolysed for a measured period using a steady current. A mass of $2.95\,\text{g}$ of tin metal forms at the cathode. $\text{Al}_2\text{O}_3(l)$ is electrolysed for the same period with the same current. Calculate the mass of aluminium metal formed at the cathode. Give your answer to three significant figures. Show your working.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: A concentration of $1\ \mathrm{mol\ dm^{-3}}$ AND a temperature of $298\ \mathrm{K}$

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