Chemistry 9701 · AS & A Level · Electrochemistry

Electrochemistry — practice question

(a)[3]

Fill in the table by identifying the substance produced at each electrode during electrolysis with inert electrodes for: AgNO$_3$(aq), concentrated NaCl(aq), and CuSO$_4$(aq).

(b(i))[2]

Molten calcium iodide, CaI$_2$, is electrolysed in an inert atmosphere using inert electrodes. Write ionic equations for the reactions at the electrodes.

(b(ii))[2]

Molten CaI$_2$ undergoes redox during electrolysis. Identify the ion that is oxidised and the ion that is reduced, and support your answer by referring to oxidation numbers.

(b(iii))[1]

Give two visual observations that would be seen during this electrolysis.

(c)[3]

An oxide of iron dissolved in an inert solvent is electrolysed for $2.00\,\text{hours}$ with a current of $0.800\,\text{A}$. The products of electrolysis are iron and oxygen. The iron collected has a mass of $1.11\,\text{g}$. Calculate the oxidation number of Fe in the oxide of iron. Show all your working.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: Correct anode and cathode products for all three electrolytes

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