Question

What colour change will occur when titrating chloride with silver nitrate solution using potassium chromate as indicator?

Answer 1

1. Potassium Chromate is used as an indicator in the determination of Chloride by titration with standard Silver Nitrate solution.
2. This method is also known as the Mohr method of determining Chloride .
3. It is based on the formation of a red precipitate of Silver Chromate at the endpoint.
4. after all the Chloride has been precipitated as white Silver Chloride

The reactions can be described as

Ag⁺ + Cl^- → AgCl (white precipitate)

2 Ag⁺ (excess) + CrO₄^2- → Ag₂CrO₄ (red precipitate at endpoint)