Oxidation and reduction

• What do oxidation and reduction reactions involve?

  Transfer of electrons
• What does OIL RIG stand for?

  Oxidation Is Loss, Reduction Is Gain
• What happens in oxidation?

  Loss of electrons occurs
• What happens in reduction?

  Gain of electrons occurs
• What is a displacement reaction of metals?

  • A more reactive metal displaces a less reactive metal
  • Occurs in metal salt solutions
  • Example: Mg displacing Cu from CuSO₄
• What is the example of a displacement reaction involving magnesium?

  Mg displaces Cu from CuSO₄
• What is a displacement reaction of halogens?

  • A more reactive halogen displaces a less reactive halogen
  • Occurs in potassium halide solutions
  • Example: Cl₂ displacing Br⁻ from KBr
• What is the example of a displacement reaction involving chlorine?

  Cl₂ displaces Br⁻ from KBr
• In displacement reactions of metals, what happens to the more reactive metal?

  It loses electrons and is oxidised
• In displacement reactions of metals, what happens to the less reactive metal?

  It gains electrons and is reduced
• What is the half equation for copper ions in the reaction with magnesium?

  Cu²⁺(aq) + 2e⁻ → Cu(s)
• What is the half equation for magnesium in the reaction with copper sulfate?

  Mg(s) → Mg²⁺(aq) + 2e⁻
• What is the ionic equation for the reaction between magnesium and copper sulfate?

  Mg(s) + Cu²⁺(aq) → Mg²⁺(aq) + Cu(s)
• What happens to halogens in displacement reactions?

  More reactive halogens gain electrons and are reduced
• What is the simplified equation for the reaction between chlorine and potassium bromide?

  Cl₂(g) + 2Br⁻(aq) → 2Cl⁻(aq) + Br₂(aq)
• What defines redox reactions?

  • One species is oxidised
  • Another species is reduced
  • Involves electron transfer
• What are variable oxidation states in transition metals?

  Transition metals can form different ions
• What is the oxidation state of iron in iron(II) chloride?

  +2
• What happens to iron(II) chloride when hydrogen peroxide is added?

  It is oxidised to iron(III) chloride
• What ion does iron(III) chloride contain?

  Fe³⁺