Solubility Rules

  1. Nitrates (NO3-) are all soluble.

  2. Alkali metal (Li+, Na+, K+, Cs+, and Rb+) and ammonium (NH4+) salts are all soluble, with the exception of a few Lithium salts.

  3. Chloride, bromide, and iodide (Cl-, Br-, and I-) salts are generally soluble, except for the salts of silver, lead(II) and mercury(I) (Ag+, Pb2+ and Hg22+).

  4. Sulfates are soluble, except for the salts of barium {BaSO4}, lead(II) {PbSO4}, mercury(II) {HgSO4}, and calcium {CaSO4}.

  5. Most hydroxides are only slightly soluble (but see rule 2).

  6. Sulfides (S2-), carbonates (CO32-), phosphates (PO43-), and chromates (CrO42-) are only slightly soluble (but see rule 2).














Balancing Redox Equations

Acid Solution:

Separate the reaction into two half-reactions.

Balance each half-reaction separately:

  1. Balance atoms other than O & H by inspection.

  2. Balance O by adding H2O to the opposite side.

  3. Balance H by addding H+ as appropriate.

  4. Balance the charge by adding electrons (e-) - add to same side as excess of positive charge, or opposite side if excess negative charge.

  5. Balance the charges of the two half-reactions by multiplying appropriately.

Add two equations together

Cancel items appearing on both sides.















Basic Solution:


© R A Paselk

Last modified 9 February 2011