# Zinc reacts with sulfuric acid according to the equation: Zn + H₂SO₄ → ZnSO₄ + H₂. A student adds a small amount of zinc powder to a large excess of sulfuric acid. Explain why the zinc is the limiting reactant in this reaction and describe what effect this has on the amount of hydrogen gas produced.

> Eduqas A-Level Chemistry — 3.6 Amines and polymers (A-Level only) · Explain · 5 marks

> Zinc reacts with sulfuric acid according to the equation: Zn + H₂SO₄ → ZnSO₄ + H₂. A student adds a small amount of zinc powder to a large excess of sulfuric acid.

## Mark scheme (5 marks)

1. The limiting reactant is the reactant that is completely used up during the reaction
2. The zinc is the limiting reactant because it limits the amount of products formed / the sulfuric acid is in excess so not all of it reacts
3. The amount of hydrogen gas produced is determined by / limited by the amount of zinc, not the amount of sulfuric acid
4. According to the equation, 1 mole of zinc produces 1 mole of hydrogen gas / the molar ratio of Zn to H₂ is 1:1
5. Once the zinc is completely used up, the reaction stops and no more hydrogen is produced even though sulfuric acid remains

## Key terms

- [limiting reactant](https://www.gradenine.co.uk/glossary/limiting-reactant)

## Related

- [Revision notes for Eduqas A-Level Chemistry](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/zinc-reacts-with-sulfuric-acid-according-0900233d) · Published by Druglandscape Ltd.