Precipitates are the salts or solids that form in a solution after a chemical reaction takes place. The solution is called precipitant. Often the compounds are identified by the color of the precipitates and their solubility or insolubility in additional concentrations of acids or solvents.
Precipitation is used for separating compounds and purifying them and for forming crystals.
Silver nitrate and potassium chloride can give silver chloride as the precipitate. The (s) means solid and precipitate. (aqua) means solution in water.