Chemistry 9701 · AS & A Level · Electrochemistry

Electrochemistry — practice question

(a)[3]

Fill in the table by identifying the substance released at each electrode during electrolysis using inert electrodes.

(b(i))[2]

Molten calcium iodide, $\text{CaI}_2$, is electrolysed in an inert atmosphere with inert electrodes. Write ionic equations for the reactions at the electrodes.

(b(ii))[2]

The electrolysis of molten $\text{CaI}_2$ is a redox process. Identify the ion that is oxidised and the ion that is reduced, and explain your answer by referring to oxidation numbers.

(b(iii))[1]

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

(c)[3]

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

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: Right products at the anode and cathode for each electrolyte

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