Answer to Question #344847 in Chemistry for Larry

Question

Balance the following redox reactions: (8pts, 4pts each)

              a) Cu (s) +  NO₃^- (aq)       à      Cu²⁺(aq)     +  NO (g)        (acidic medium)

Oxidation Half Reaction:

Reduction Half Reaction:

Net Reaction:

 

 

 

              b)  MnO₄^- (aq) +  NO₂^-(aq)        à   Mn²⁺ (s)   +  NO₃^- (aq)     (basic medium)

Oxidation Half Reaction:

 

Reduction Half Reaction:

 

Net Reaction:

 

 

Answer 1

Solution:

a) Cu(s) + NO₃⁻(aq) → Cu²⁺(aq) + NO(g) (acidic medium)

Oxidation half reaction:

Cu(s) − 2e⁻ → Cu²⁺(aq)

Reduction half reaction:

NO₃⁻(aq) + 4H⁺(aq) + 3e⁻ → NO(g) + 2H₂O(l)

Net reaction:

3Cu(s) + 2NO₃⁻(aq) + 8H⁺(aq) → 3Cu²⁺(aq) + 2NO(g) + 4H₂O(l)

b) MnO₄⁻(aq) + NO₂⁻(aq) → MnO₂(s) + NO₃⁻(aq) (basic medium)

Oxidation half reaction:

NO₂⁻(aq) + 2OH⁻(aq) − 2e⁻ → NO₃⁻(aq) + H₂O(l)

Reduction half reaction:

MnO₄⁻(aq) + 2H₂O(l) + 3e⁻ → MnO₂(s) + 4OH⁻(aq)

Net reaction:

3NO₂⁻(aq) + 2MnO₄⁻(aq) + H₂O(l) → 3NO₃⁻(aq) + 2MnO₂(s) + 2OH⁻(aq)