What would happen with non-electrolytes?
4 marks · NormalYou are given a white solid (substance Y) that is soluble in water. You need to determine whether it is an ionic compound, a covalent compound, or a non-electrolyte.
Describe an experiment you could do to determine the type of substance.
State what you would observe if substance Y is an ionic compound and explain your answer.
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) Dissolve the solid in water, set up the solution with two electrodes connected to a power supply and a bulb, and observe if the bulb lights up (or use a conductivity tester).
(b) If Y is ionic, the bulb will light up (or the tester shows conduction), showing electric current is flowing because ions in the solution carry the charge.
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Suggests dissolving in water and using a circuit with electrodes and a bulb or a conductivity meter.
B2 (a) · 1 mark · States to observe whether the bulb lights or the tester indicates conduction.
B3 (b) · 1 mark · States that the bulb will light (or current will flow) if ionic.
B4 (b) · 1 mark · Explains that ions in solution carry charge and enable conduction.
Worked solution
a) Dissolve substance Y in water. Set up an electrical circuit with two electrodes in the solution, connected to a bulb or a conductivity meter. If the bulb lights or the meter registers current, the substance conducts electricity.
b) If Y is ionic, the bulb will light up. This is because the dissolved ions are free to move and carry electric current.