Balancing and Oxidation Numbers

1.	Balance each of the following redox reactions using the half reaction method for acidic solutions:

a.	MnO4- (aq) +  Ag  (s) → Mn2+ (aq) +  Ag+  (aq)
b.	Hg (s) +  NO3- (aq) +  Cl- (aq) → HgCl42- (aq) +  NO2 (aq)
c.	AsH3  +  Zn2+  →  H3AsO4  +  Zn
d.	I3- (aq)  →   I- (aq) +  IO3-  (aq) [Note: I3- (aq) is found in both half reactions
e.	I¯ (aq)  +  ClO¯(aq)       I3¯(aq)   +   Cl¯(aq)
f.	As2O3 (s)   +   NO3¯ (aq)       H3AsO4 (aq)   +   NO (g)
g.	Br¯ (aq)   +   MnO4¯ (aq)      Br2 (l)   +   Mn2+ (aq)
h.	CH3OH (aq)    +   Cr2O72- (aq)     CH2O(l)   +    Cr3+(aq)
i.	Mn2+(aq)   +   BiO3¯ (aq)       Bi3+(aq)  +   MnO4¯ (aq)
j.	S8 (s)   +   NO3¯ (aq)       SO32- (aq)    +    NO (g) 
k.	H3AsO4 (aq)   +   Zn (s)      AsH3 (g)   +   Zn2+ (aq)
l.	P4 (s)   +   Cr2O72- (aq)      H3PO4 (aq)   +   Cr3+ (aq)    

2.	Balance each of the following redox reactions using the half reaction method for basic solutions:

a.	CN-  (aq) +  MnO4-  (aq)  →  CNO- (aq) +   MnO2  (s)
b.	H2O2 (aq) +  ClO2 (g) →  ClO2- (aq) +  O2  (g)
c.	ClO- (aq) +  CrO2- (aq) →   CrO42- (aq) +  Cl2 (g)
d.	Al (s) +  NO2- (aq) →  NH3 (aq) +  AlO2- (aq)
e.	Al(s)   +   MnO4¯ (aq)      MnO2(s)    +    Al(OH)4¯ (aq)
f.	NO2¯ (aq)   +   Al(s)     NH3(aq)   +   AlO2¯ (aq)
g.	Cr(s)   +   CrO42-(aq)      Cr(OH)3(s) [Note:  Cr(OH)3 is found in BOTH half reactions!]  
h.	MnO4¯ (aq)  +  S2-(aq)      MnO2(s)     +    SO32-(aq)
i.	Cl2(aq)   +    Br2(l)              OBr¯ (aq)      +   Cl¯ (aq)
j.	H2O2(aq)   +   I¯ (aq)    IO3¯ (aq)  [Note:  IO3¯ is found in both half reactons!]
k.	NO3¯ (aq)  +   NH3(aq)      NO2¯ (aq)
l.	S8(aq)   +   MnO4¯ (aq)     SO42-(aq)  +  MnO2(s)

3.	Iodine reacts with concentrated nitric acid to form iodic acid, gaseous nitrogen dioxide and water. 

a.	Write the chemical equation showing the products and the reactants.
b.	Balance using oxidation number method.

4.	Ammonium ions, from fertilizers or animal waste, are oxidized by atmospheric oxygen. The reaction results in the acidification of soil on farms and the pollution of ground water with nitrate ions.

a.	Write the ionic equation for this reaction.
b.	Balance using oxidation number method.