Most of the reactions we will see during our course fall into three broad categories:

• precipitation reactions
• reactions of acids
• reduction-oxidation reactions ("redox")

The first category is the simplest. Precipitation reactions occur between ionic compounds (electrolytes). The same "script" is always followed. The positive ion from each compound pairs up with the negative ion from the other. In effect, the ions "change partners":

silver nitrate + sodium chloride → silver chloride + sodium nitrate