ANSWER KEY
Class Examples. All reactions occur in acidic solution (H+ and H2O will be added).
1.
Cr2O7 2- (aq) + NO2 1- (aq) → Cr 3+ (aq) + NO3 1- (aq)
Cr2O7 2- (aq) + 3 NO2 1- (aq) + 8 H + (aq) → 2 Cr 3+ (aq) + 3 NO3 1- (aq) + 4 H2O (l)
(6 electrons involved in the rxn)
2.
As (s) + ClO3 1- (aq) → H3AsO3 (aq) + HClO (aq)
4 As (s) + 3 ClO3 1- (aq) + 3 H + (aq) + 6 H2O (l) → 4 H3AsO3 (aq) + 3 HClO (aq)
(12 electrons involved in the rxn)
3.
MnO4 1- (aq) + Cl1- (aq) → Mn2+ (aq) + Cl2 (g)
2 MnO4 1- (aq) + 10 Cl 1- (aq) + 16 H + (aq) → 2 Mn2+ (aq) + 5 Cl2 (g) + 8 H2O (l)
(10 electrons involved in the rxn)
4.
Cl2 (g) + S2O3 2- (aq) → Cl 1- (aq) + SO4 2- (aq)
4 Cl2 (g) + S2O3 2- (aq) + 5 H2O (l) → 8 Cl 1- (aq) + 2 SO4 2- (aq) + 10 H + (aq)
(8 electrons involved in the rxn)