The electrolysis of aqueous solutions
3 marks · EasyA student is asked to investigate the electrolysis of an aqueous sodium chloride solution in the laboratory.
Describe how you would set up apparatus to collect the products formed during this electrolysis.
State one safety precaution you should take when performing this experiment.
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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(a) — · must show use of a beaker/glass tube with sodium chloride solution, use of two carbon electrodes, connecting electrodes to a battery, collection of gases with test tubes over electrodes
(b) Carry out the experiment in a fume cupboard or well-ventilated area / Wear eye protection / Do not inhale chlorine / Switch off power once chlorine is detected.
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Marking points
M1 (a) · 1 mark · Describes setting up carbon electrodes in a beaker or glass tube containing sodium chloride solution and connecting to a battery.
M2 (a) · 1 mark · Describes collection of gases with test tubes inverted over electrodes (or alternative correct collection method).
B1 (b) · 1 mark · States a relevant safety precaution: fume cupboard / ventilation/ eye protection / avoid inhaling chlorine / turn off power once chlorine detected.
Worked solution
a) Set up a beaker with concentrated sodium chloride solution. Insert two carbon electrodes and connect them to a battery. Place an inverted test-tube filled with the solution over each electrode to collect any gases formed.
b) Carry out the experiment in a fume cupboard, or wear eye protection, or avoid inhaling chlorine gas.