# Methanoic acid (HCOOH) is a weak acid. Sulfuric acid (H₂SO₄) is a strong acid. Both acids are prepared as solutions of equal concentration. Explain why the methanoic acid solution has a higher pH than the sulfuric acid solution of equal concentration.

> Edexcel A-Level Chemistry (9CH0) — 12.1 Strong and weak acids · Explain · 5 marks

> Methanoic acid is found naturally in ant venom. Sulfuric acid is a strong acid used widely in industry. Equal concentrations of the two acids are prepared in separate beakers.

## Mark scheme (5 marks)

1. Sulfuric acid is fully/completely dissociated (in solution) / ionised
2. Methanoic acid is partially/only slightly dissociated (in solution) / ionised
3. Therefore the sulfuric acid solution contains a greater concentration of H⁺ (hydrogen/hydronium) ions than the methanoic acid solution (at equal concentrations)
4. pH is a measure of hydrogen ion concentration / higher H⁺ concentration gives a lower pH
5. The reversible nature of weak acid dissociation means equilibrium lies to the left, so most molecules remain undissociated

## Key terms

- [weak acid](https://www.gradenine.co.uk/glossary/weak-acid)
- [strong acid](https://www.gradenine.co.uk/glossary/strong-acid)
- [pH](https://www.gradenine.co.uk/glossary/ph)

## Related

- [Revision notes for Edexcel A-Level Chemistry (9CH0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/methanoic-acid-hcooh-is-a-weak-1ee01f53) · Published by Druglandscape Ltd.