Acid-Metal Reactions in Terms of Redox

  • Only metals above hydrogen in the reactivity series will react with dilute acids.
  • The more reactive the metal then the more vigorous the reaction will be.
  • Metals that are placed high on the reactivity series such as potassium and sodium are very dangerous and react explosively with acids.
  • When acids react with metals they form a salt and hydrogen gas:
  • The general equation is:

Acid + metal ⟶ salt + hydrogen

Examples:

Reactions of Acids with Metals Table, IGCSE & GCSE Chemistry revision notes

  • Magnesium, zinc and iron all react with hydrochloric and sulfuric acid.

Reactions of Acids with Metals 2 Table, IGCSE & GCSE Chemistry revision notes

Identifying the Reduced/Oxidised Species

  • Metal-acid reactions are redox reactions.
  • If we analyse the ionic equation for the reaction between zinc and hydrochloric acid:

Zn + 2HCl ⟶ ZnCl + 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.

AQA GCSE Chemistry Notes

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Morgan Curtin Chemistry

Author: Morgan

Morgan’s passion for the Periodic Table begun on his 10th birthday when he received his first Chemistry set. After studying the subject at university he went on to become a fully fledged Chemistry teacher, and now works in an international school in Madrid! In his spare time he helps create our fantastic resources to help you ace your exams.