Balance the chemical equations below. Indicate the species being oxidized, reduced and the number of electrons transferred in the balanced equation respectively.

Question

Balance the chemical equations below. Indicate the species being oxidized, reduced and the number of electrons transferred in the balanced equation respectively.

(a)MnO₄^-(aq) + ClO^-(aq) →MnO₂(s) + ClO₂^-(aq) (under basic condition)

(b) NO₂^-(aq) + Al(s) → N₂O(g) + AlO₂^-(aq) (under basic condition)

(c) Cu(s) + SO₄^2-(aq) → Cu²⁺(aq) + SO₂(g) (under acidic condition)

Answer 1

There is a space limit that Wyzant imposes so I can't answer all at one time.

(a)MnO₄^-(aq) + ClO^-(aq) →MnO₂(s) + ClO₂^-(aq) (under basic condition) 

MnO₄^- ==> MnO₂ ... reduction since Mn is reduced from 7+ to 4+ 

MnO₄^- ==> MnO₂ + 2H₂O .. to balance oxygen

MnO₄^- + 4H₂O ==> MnO₂ + 2H₂O + 4OH^- .. to balance hydrogen in basic conditions

MnO₄^- + 4H₂O + 3e- ==> MnO₂ + 2H₂O + 4OH^- .. to balance charge

MnO₄^- + 2H₂O + 3e- ==> MnO₂ + 4OH^- .. balanced for both mass and charge 

ClO^- ==> ClO₂^- ... oxidation since Cl is oxidized from 1+ to 3+

ClO^- + H₂O ==> ClO₂^- .. to balance oxygen

ClO^- + H₂O + 2OH- ==> ClO₂^- + 2H₂O .. to balance hydrogen in basic conditions

ClO^- + H₂O + 2OH- ==> ClO₂^- + 2H₂O + 2e- .. to balance charge

ClO^- + 2OH- ==> ClO₂^- + H₂O + 2e- .. balanced for mass and charge

MnO₄^- + 2H₂O + 3e- ==> MnO₂ + 4OH^- multiply by 2 to equalize electrons

ClO^- + 2OH- ==> ClO₂^- + H₂O + 2e- multiply by 3 to equalize electrons

2MnO₄^- + 4H₂O + 6e- + 3ClO^- + 6OH- ==> 2MnO₂ + 8OH^- + 3ClO₂^- + 3H₂O + 6e- (combine and cancel)...

2MnO₄^- + H₂O + 3ClO^- ==> 2MnO₂ + 2OH^- + 3ClO₂^- BALANCED REDOX EQUATION (6 ELECTRONS)