Preparation of a standard solution for free chlorine
Cat.No. 100316 Hydrochloric acid 25 % for analysis
Cat.No. 105614 Sodium hypochlorite solution (6 - 14 % active chlorine)
Preparation of a stock solution of free chlorine:
First prepare a 1:10 dilution using a sodium hypochlorite solution containing approximately 6 - 14 % of active chlorine.
Precise assay of the stock solution for free chlorine: Pipette 10.0 mL of the stock solution into a 250-mL ground-glass-stoppered conical flask containing 60 mL of water for analysis.
1 mL sodium thiosulfate solution = 3.55 mg free chlorine