AQA GCSE Chemistry

Revision Notes

4.2.2 Metal & Acid Reactions as Redox Reactions

Higher Tier Only

Metals & Acid Reactions as Redox Reactions

  • Metal-acid reactions are redox reactions
  • Redox means reduction and oxidation at the same time
  • If we analyse the ionic equation for the reaction between zinc and hydrochloric acid:

Zn + 2HCl ZnCl2 + H2

  • The ionic equation is:

Zn + 2H+ Zn2+ + H2

  • This equation can be further split into two half equations illustrating oxidation and reduction individually:

Zn → Zn2+ + 2e

2H+ + 2e→ H2

  • The zinc atoms are thus oxidised as they lose electrons.
  • The hydrogen ions are thus reduced as they gain electrons.
  • Both reactions are occurring at the same time and in the same reaction chamber hence it is a redox reaction

Exam Tip

Remember metal atoms tend to lose electrons and in these reactions are usually the species that undergoes oxidation.

Author: Francesca

Fran has taught A level Chemistry in the UK for over 10 years. As head of science, she used her passion for education to drive improvement for staff and students, supporting them to achieve their full potential. Fran has also co-written science textbooks and worked as an examiner for UK exam boards.

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