1. PRACTICAL SKILLS ON THE TOPIC DETERMINATION OF RESIDUAL CHLORINE IN WATER

2. PURPOSE This skill is required when selecting the dose of chlorine, as well as to assess the quality of chlorinated water.

3. EQUIPMENT NEEDED: The study chlorinated water Chemical glassware reagent

4. SEQUENCE OF ACTIONS 1- Pour into a flask with 250 ml of water under investigation

5. 2- Add 5 ml of 5% potassium iodide, 5 ml of buffer solution and 1 ml of 1% starch solution.

6. 3- Perform the titration of the sample 0.001% solution of sodium hyposulphite to blue discoloration in the flask.

7. 4- Calculate the residual chlorine by the formula: X = (nx K x 0,355 x 1000): 250 mg / l, where n- number of hyposulphite (ml) that went to the titration of the sample K - correction factor titer hyposulphite.

8. 5 Rate the results obtained with the hygienic standards of residual chlorine.