1. The document describes the argentometric titration method to determine the chloride ion concentration in water. Silver nitrate (AgNO3) is used as the titrant and reacts with chloride ions to form insoluble silver chloride precipitate. 2. The procedure involves standardizing the silver nitrate solution against a standard sodium chloride solution. Then, an unknown water sample is titrated with the standardized silver nitrate solution. 3. The chloride ion concentration in the water sample is calculated based on the volume of silver nitrate used and its known normality. The amount of chloride ion present per liter of sample water is reported as the result.