Zinc, iron and copper are metals that can react with dilute sulfuric acid. Describe what happens when zinc is added to dilute sulfuric acid, and explain why copper does not react with dilute sulfuric acid.

AQA GCSE Chemistry (8462) — 4.4.2 Reactions of acids · Describe and Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

Zinc reacts with dilute sulphuric acid to give zinc sulphate and hydrogen gas:

Zn(s) + H₂SO₄(aq) → ZnSO₄(aq) + H₂(g)

The reaction is seen as effervescence – bubbles of H₂ are released.

Copper does not react because it lies below hydrogen in the reactivity series. A metal must be more reactive than hydrogen to displace H⁺ ions from the acid; copper is not, so no reaction occurs.

Examiner tips

  • Show the balanced equation for zinc – this gives 2 marks. Mention the effervescence – 1 mark. Explain copper’s position in the reactivity series – 1 mark.
  • common_mistakes
  • :
  • Writing the wrong product (e.g. CuSO₄) for copper. Forgetting to mention the effervescence. Saying copper reacts because it is a metal – ignores reactivity series.

Mark scheme (4 marks)

  1. Zinc reacts with dilute sulfuric acid to produce zinc sulfate (and hydrogen gas)
  2. Hydrogen gas is produced / bubbles / effervescence observed
  3. Copper is less reactive than hydrogen (or below hydrogen in the reactivity series)
  4. A more reactive element is needed to displace hydrogen from the acid / copper cannot displace hydrogen ions from the acid

Key terms in this question

dilute sulfuric acid

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