Procedure
Follow these steps to determine the concentration of chloride ions in a sample:
1. Pipette out 20 ml of water sample into a clean and dry conical flask.
2. To this solution add 2 drops of 2% K2CrO4 indicator.
3. Fill the burette with N/100 AgNO3 solution and note down the initial reading as indicated by the lower meniscus.
4. Titrate the reaction mixture against N/100 AgNO3 solution, during titration the color of the solution changes yellow to reddish brown, continue the titration till no further change is observed in the color of reaction mixture, this volume is measured as end point.
5. The titration is repeated for concordant values.
Safety Precautions:
1. Clamp burette vertically.
2. Before use rinse the burette thoroughly, while filling the burette no air bubble should be in the burette.
3. After filling of the burette remove the funnel.
4. Read the lower meniscus of the burette.
5. During titration, titration flask should be continuously stirred.
6. To get better visibility of color change at the end point use filter paper below the conical flask.
7. Add same amount of indicator in each titration.