The indicator used for testing chlorides is?

The indicator used for testing chlorides is potassium chromate. Potassium chromate reacts with silver nitrate in the presence of chloride ions to form a distinct colored precipitate of silver chloride, which can be visually observed when testing for the presence of chlorides in a solution.

When silver nitrate is added to a solution containing chlorides, the silver ions from the silver nitrate will react with the chloride ions to form an insoluble, white precipitate of silver chloride. The addition of potassium chromate introduces a clear indication for the endpoint of the titration. Specifically, once all chloride ions have reacted, any excess silver ions will then react with the chromate to form a reddish-brown precipitate of silver chromate, signaling the completion of the reaction.

Understanding this reaction is crucial for accurately measuring chloride levels, particularly in water quality testing, where excessive chloride can indicate pollution or saltwater intrusion.