Solid calcium chloride cannot be electrolysed.
Give one reason why.
How to approach this question
For a substance to conduct electricity and be electrolysed, it must contain charged particles that are free to move. What are the charged particles in calcium chloride, and what is their state in a solid?
Full Answer
The ions are not free to move.
Electrolysis requires the movement of ions to carry charge through the electrolyte and to the electrodes. In solid ionic compounds like calcium chloride, the positive (Ca²⁺) and negative (Cl⁻) ions are held in fixed positions within a strong crystal lattice structure. Because the ions are not free to move, solid calcium chloride cannot conduct electricity and therefore cannot be electrolysed.
Common mistakes
✗ Saying "it has no free electrons" - ionic compounds conduct via ions, not electrons.
✗ Saying "it is a solid" - this is not a full explanation. You must explain *why* being a solid prevents electrolysis.
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