Estimation of free residual chlorine by Titration method (FRC)

The free residual chlorine test is a laboratory analysis conducted to determine the concentration of free residual chlorine in a water sample. Free residual chlorine refers to the amount of chlorine that remains in water after it has reacted with impurities and is available for disinfection purposes. Here's a brief overview of the laboratory procedure for the free residual chlorine test:  Sample Collection: Collect a Test water sample from the source you want to test. Ensure that the sample is collected in a clean container to avoid contamination.  Reagents and Equipment: Arrange the necessary reagents and equipment for the test. Commonly used reagents include sodium thiosulphate solution (N/50) . Thiosulphate with free chlorine to produce a color change.  Test Procedure: a. Add the reagent to the water sample. The reagent will react with free chlorine to produce a deep violet to colorless. Procedure : Take 10.0 ml of 10% KI (Potassium Iodide) solution in stoppered 250 ml conical flask. Add 50.0 ml water of test sample holding the point of the pipette just above the iodine solution and put the stoppered. Insure it should be well tight. Shake the conical flask vigorously for five minutes well. Remove the stopper, wash the adhering solution into the flask with about 5-10 ml distilled water. Titrate it the solution against N/50 Solution of sodium thiosulphate using starch indicator as final indicator. The indicating of end point is confirm by the change of color from deep violet to colorless solution B.R. X Normality x 35.45 x 1000 Formula for calculation: ------------------------------------------------- Sample taken  Reporting: The results are typically reported in terms of chloride concentration, often in units such as milligrams per liter (mg/L) or parts per million (ppm). The free residual chloride test is crucial in various industries, including water treatment, where it helps ensure that water meets regulatory standards and is safe for consumption or other uses. Additionally, monitoring chloride levels is important in preventing corrosion in industrial processes and assessing environmental impact.