Chemistry 9701 · AS & A Level · Electrochemistry

Electrochemistry — practice question

(a)[3]

Complete the table by predicting which substance is released at each electrode during electrolysis with inert electrodes for: $\text{NaOH}(aq)$, dilute $\text{CuCl}_2(aq)$ and concentrated $\text{MgCl}_2(aq)$.

(b(i))[3]

The electrolysis of molten $\text{ZnBr}_2$ is a redox reaction. Identify the ion that undergoes oxidation and the ion that undergoes reduction. Use ionic half-equations to justify your answer.

(b(ii))[1]

Describe one visual observation that would be seen during this electrolysis.

(c)[3]

Using inert electrodes, dilute sulfuric acid is electrolysed for $50.0$ minutes at a current of $1.20\,\text{A}$. A different gas is collected above each electrode, and the volumes of both gases are measured under room conditions. Calculate the maximum volume of gas that could be collected at the cathode. $\text{volume} = \ldots\,\text{cm}^3$

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Right anode/cathode products for NaOH(aq), CuCl$_2$(aq), conc MgCl$_2$(aq)

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