Preparation of the sample: The sample containing chloride ions is dissolved in water to obtain a clear solution.
Acidification of the sample: Glacial acetic acid is added to the sample solution to make it acidic. The acidification step helps in the complete precipitation of chloride ions as AgCl.
Addition of silver nitrate solution: Silver nitrate (AgNO3) solution is added to the acidified sample. Ag+ ions from silver nitrate react with Cl- ions from the sample to form a white precipitate of AgCl.
Digestion and filtration: The mixture is heated gently to facilitate the complete precipitation of AgCl. The precipitate is then filtered through a filter paper to separate it from the solution.
Washing: The AgCl precipitate is washed with water to remove any impurities or excess silver nitrate solution.
Dissolution of AgCl: The AgCl precipitate is dissolved in hot concentrated ammonia solution (NH4OH). This step converts the AgCl precipitate into a soluble complex, [Ag(NH3)2]Cl.
Reprecipitation of AgCl: Nitric acid (HNO3) is added to the solution containing the [Ag(NH3)2]Cl complex to reprecipitate AgCl. The reprecipitation step ensures complete precipitation of chloride ions.
Filtration and drying: The AgCl precipitate is filtered again and dried in an oven at a suitable temperature.
Weighing: The dried AgCl precipitate is weighed. The weight of AgCl is used to calculate the chlorine content in the sample.
The mass of chlorine in the sample can be calculated using the following formula:
Mass of chlorine (Cl) = (Mass of AgCl precipitate - Mass of empty crucible) × (Atomic weight of Cl / Molecular weight of AgCl)
By determining the mass of chlorine in the sample, the chlorine content can be expressed in percentage or any other desired unit.
