The formation of a precipitate can be predicted by the following simple solubility guidelines for inorganic compounds in water. Be aware that these are only guidelines and that many exceptions do occur.
The following salts are soluble…
salts of Li+, Na+, K+ and NH4+ (ammonium ion)
salts of NO3- (nitrate), and C2H3O2- (acetate)
chloride, bromide and iodide salts except for AgX and PbX2