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CAIE IGCSE Chemistry 7.1.10 Strong acid as an acid that is

CAIE IGCSE Chemistry 7.1.10 Strong acid as an acid that is
Cambridge IGCSE Chemistry 0620 syllabus for exams in 2026, 2027 and 20282026–2028

Practise comparing strong and weak acids by dissociation, H+(aq) concentration, pH and reaction rate at the same concentration.

How this is tested

  • define strong acids as completely dissociated and weak acids as partially dissociated in water
  • compare pH and H+(aq) concentration for hydrochloric acid and ethanoic acid
  • use magnesium reaction rates to infer stronger or weaker acid behaviour

Question 19

[Maximum number: 1]

Two acids, P and Q, with the same concentration and volume are reacted separately with the same mass of magnesium ribbon.

The reactions produce the same total volume of hydrogen gas but acid Q reacts much more slowly than acid P.

Which explanation for the difference between P and Q is correct?

A

Acid P has a higher pH than acid Q.

B

Acid P has a lower concentration of hydrogen ions.

C

Acid Q is partially dissociated and acid P is fully dissociated.

D

Acid Q is a proton acceptor.