Why we use K2CRO4 indicator?

K2CrO4 (potassium chromate) is commonly used as an indicator in titrations involving silver ions, particularly in the determination of chloride ions. When silver nitrate is added to a solution containing chloride, it forms a precipitate of silver chloride. The K2CrO4 indicator helps to indicate the endpoint of the titration by forming a reddish-brown precipitate of silver chromate when all chloride ions have reacted, signaling that the silver ions are in excess. This visual change provides a clear and distinct endpoint for accurate measurements.