Outline the Mohr method for the titrimetric determination of chloride. Write thestoichiometric equations of the precipitation reactions involved. Explain how the end pointof the titration is detected and write the corresponding stoichiometric equation.

The Mohr method for the titrimetric determination of chloride involves the titration of chloride ions with a silver nitrate solution. The method is named after the German chemist Karl Friedrich Mohr, who first developed it. Here is a step-by-step outline of the process:

1. The sample containing chloride ions is dissolved in distilled water.
2. A few drops of potassium chromate indicator are added. This gives the solution a yellow color.
3. The solution is then titrated with a standard solution of silver nitrate.

The stoichiometric equation for the precipitation reaction is:

Ag+ (aq) + Cl- (aq) -> AgCl (s)

This reaction continues until all the chloride ions have reacted with the silver ions to form a white precipitate of silver chloride.

The end point of the titration is detected when all the chloride ions have reacted and the next drop of silver nitrate reacts with the chromate ions to form a red-brown precipitate of silver chromate. This indicates that all the chloride ions have been precipitated and the amount of silver nitrate added is equal to the amount of chloride in the sample.

The stoichiometric equation for this reaction is:

2Ag+ (aq) + CrO4 2- (aq) -> Ag2CrO4 (s)

By knowing the volume of silver nitrate solution used, one can calculate the amount of chloride in the sample.