Question

Classify the half‑reactions as reduction half‑reactions or oxidation half‑reactions. H2(g)⟶2H+(aq)+2e− 12O2(g)+2H+(aq)+2e−⟶H2O(g) Cd(s)+2OH−(aq)⟶Cd(OH)2(s)+2e− 2NiO(OH)(s)+2H2O(l)+2e−⟶2Ni(OH)2(s)+2OH−(aq) Fe(s)⟶Fe2+(aq)+2e− Answer

Answer 1

Answer:The 1st reaction is oxidation half reaction

              The 2nd reaction is reduction half reaction

              The 3rd reaction is oxidation half reaction

              The 4th reaction is reduction half reaction

              The 5th reaction is oxidation half reaction

Explanation:

Oxidation half reactions are those reactions  in which the active species undergoes oxidation.

Reduction half reactions are those reactions in which the active species undergoes reduction.

H₂(g)⟶2H+(aq)+2e⁻ ,It is a oxidation half reaction as H₂ is oxideised to H⁺.

1/2O₂(g)+2H+(aq)+2e⁻⟶H₂O(g), It is a reduction half reaction as O₂ is reduced to H₂O.

Cd(s)+2OH−(aq)⟶Cd(OH)₂(s)+2e⁻ , It is a oxidation half reaction as Cd is oxidised to  Cd(OH)₂.

2NiO(OH)(s)+2H₂O(l)+2e⁻⟶2Ni(OH)₂(s)+2OH−, It is a reduction half reaction as NiO(OH) to  Ni(OH)₂.

Fe(s)⟶Fe²⁺(aq)+2e⁻, It is a oxidation half reaction as Fe is oxidised to Fe²⁺.