¹All ionic compounds, even the least soluble ones, dissolve to some slight extent in water.  Thus, the "Insoluble" classification really means ionic compounds that have very limited solubility in water.  Remember that salts containing the "Insoluble" anions are always soluble with Group IA metals and ammonium ions.

Balancing Redox (Oxidation-Reduction) Reactions

After you identify the elements (or compounds) that will be oxidized or reduced, set up two half-reactions, one for oxidation (loss of electrons) and for reduction (gain of electrons).  You do not need to determine which one is oxidation or reduction, but you need to identify the correct compounds, or elements, that change oxidation state.

1. Balance the number of atoms¹
2. Balance the number of oxygen atoms by adding water²
3. Balance the number of hydrogen atoms by adding H⁺ (protons)³
4. Balance charge by adding electrons (e^-) to the side with the most positive (least negative) charge⁴
5. Balance the number of electrons gained and electrons lost⁵
6. For reactions in base (OH^-), as your last step, add OH^- ions to each side to convert H⁺'s into water

¹Balance the non-oxygen and non-hydrogen atoms, which are usually those undergoing oxidation or reduction
²Add water to make the number of O-atoms the same on both sides
³Add H⁺ to make number of H-atoms the same on both sides
⁴Determine the charge on each side; add enough electrons to make charge same on both sides (electrons added to least negative side, or most positive side).
⁵If necessary multiply each reaction by an interger to give same number of electrons gained and lost

Example Redox Balancing:

Reaction to Balance: Cu + HNO₃ → Cu²⁺ + NO₂
Copper Half Reaction: Cu → Cu²⁺ + 2e-
Nitrogen Half Reaction: 1e- + H⁺ + HNO₃ → NO₂ + H₂O  or  x2 (1e- + H⁺ + HNO₃ → NO₂ + H₂O)
Final Nitrogen Half Reaction: 2e- + 2H⁺ + 2HNO₃ → 2NO₂ + 2H₂O
Final Equation: Cu + 2H⁺ + 2HNO₃ → Cu²⁺  2NO₂ + 2H₂O