Chemistry 0620 · IGCSE · Electrolysis

Electrolysis — practice question

This question concerns electrolysis.
(a)[3]

Complete the definition of electrolysis by inserting the missing words. The decomposition of [BLANK] compounds when molten or [BLANK] by the passage of an electric current.

(b(i))[1]

State whether the mass of the cathode increases, decreases or stays the same when platinum electrodes are used.

(b(ii))[1]

Describe the change in appearance, if any, of the electrolyte when platinum electrodes are used.

(b(iii))[1]

Describe what is seen at the anode when platinum electrodes are used.

(b(iv))[3]

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

(c(i))[1]

State whether the mass of the cathode increases, decreases or stays the same when copper electrodes are used.

(c(ii))[1]

Describe the change in appearance, if any, of the electrolyte when copper electrodes are used.

(d(i))[1]

Name this ore of aluminium.

(d(ii))[1]

Name the substance added to this process to reduce the operating temperature.

(d(iii))[2]

Explain why the anodes need to be continually replaced during this process.

Worked solution & mark scheme

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