The electrolysis of aqueous solutions

2 marks · Normal

Give two observations you could make during the electrolysis of concentrated sodium chloride solution that would indicate a reaction is taking place.

Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.

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Also accept: bubbles at electrodes; gas collected in test tubes; change in colour at anode

Common mistakes: Vague answers such as 'a reaction occurs'

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Marking points

B1 · 1 mark · Mentions observation of bubbles at electrodes

B2 · 1 mark · Mentions gas collection or another valid observation (e.g., bleached paper for chlorine present)

Worked solution

1. Bubbles of gas forming at the electrodes indicate gas release.

2. Gas being collected in the test tubes above the electrodes.