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