Chemistry · May / June 2026 · Paper 12 · Question 18

Two solutions are prepared. • Solution P is 0.050 mol/dm3 hydrochloric acid. • Solution Q is 0.100 mol/dm3 butanoic acid. A 2 cm strip of magnesium ribbon is put into 100 cm3 of each solution. Fizzing is seen in both solutions, but the fizzing is faster in solution P than it is in solution Q. Which statement helps to explain this observation?

1. AMagnesium reacts with solution P to form a salt, but does not form a salt with solution Q.
2. BMore particles are dissociated in solution P than are dissociated in solution Q.
3. CSolution Q contains a stronger acid than solution P.
4. DThe particles are closer together in solution Q than they are in solution P.

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