Chemistry 0620 · IGCSE · Electrolysis

Electrolysis — practice question

In the apparatus shown, a student performs an electrolysis experiment. The student makes use of dilute aqueous sodium chloride.
(a)[1]

Give the name applied to any solution that undergoes electrolysis.

(b(i))[2]

Complete the ionic half-equation for this reaction. $[BLANK]OH^-(aq) \rightarrow [BLANK] + O_2(g) + 4e^-$

(b(ii))[1]

Explain how the ionic half-equation shows that the hydroxide ions are oxidised.

(c)[1]

Describe what the student sees at the cathode.

(d)[2]

Write the ionic half-equation for the reaction at the cathode.

(e(i))[2]

Describe what the student observes at: • the cathode • the anode.

(e(ii))[2]

State the colour observed in the solution. Give a reason for your answer.

(f)[1]

State another element that could be used in place of carbon.

Worked solution & mark scheme

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