The electrical conductivity of ionic substances

2 marks · Normal

State two states of ionic substances in which they conduct electricity. For each state, give a reason why conduction is possible.

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Molten (because ions can move) and aqueous (because ions are free).

Must show: molten: ions move, aqueous: ions move

Also accept: When molten: ions are free. When aqueous: ions are free.

Common mistakes: Stating solid; Mentioning electrons

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Marking points

B1 · 1 mark · Mentions molten or liquid state and reason (ions can move).

B2 · 1 mark · Mentions aqueous solution and reason (ions can move).

Worked solution

Ionic substances conduct electricity when molten because the ions are free to move. They also conduct when dissolved in water (aqueous) for the same reason.