ExpertEasy1 markShort Answer
AQA GCSE · Question 05.2 · Chemical changes
Solid calcium chloride cannot be electrolysed.
Give one reason why.
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
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.
Practice the full AQA GCSE Chemistry Higher Tier Paper 1
44 questions · hints · full answers · grading
More questions from this exam
Q01.1A student produced a salt by reacting copper carbonate with sulfuric acid.
This is the method use...EasyQ01.2Give one observation the student could make during Step 4 which shows that the copper carbonate i...EasyQ01.3Give one reason for filtering the mixture in Step 5.EasyQ01.4Name the equipment that can be used to warm the filtrate gently in Step 6.EasyQ01.5The maximum theoretical mass of the salt that could be produced using 50 cm³ of the sulfuric acid...Medium