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Ted Mooney, P.E. RET
The authoritative public forum
for Metal Finishing 1989-2025
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Methods of analyses
I am looking for a method for analyses to NaOCl,if you know any method please tell me.
Paulo SÈrgio Martins Alvares- Londrina, Pr, Brazil
2001
2001
Senhor Martins Alvares,
You should dissolve 0.5 g of soluble starch in 5 ml of cold demi water and add 95 ml of boiling water (add 0.1 soln of salicilic acid as preserver). As titrating agent you should use sodium thiosulphate ⇦ this on eBay or Amazon [affil links] 0.1N. 25 ml of NaOCl are diluted to 1000 ml. 25 ml of this solution are put in a 250 ml flask, containing 50 ml of water, 20 ml of KJ (Potassium iodide) 10% and 10 ml of conc. acetic acid ⇦ this on eBay or Amazon [affil links] (keep the 25 ml pipette [pipettes on eBay or Amazon [affil links] tip slightly immerse into the solution). Titration follows: when solution colour changes from dark brown to light yellow, add 1 ml of starch solution. Titration ends when the blue colour disappears.
Results
Active Chlorine (g Cl/litre) = (ml thiosulphate*0.1*35.46)/0.625 where 0.625 is the actual NaOCl employedBest regards
Francesco Cicchetti
- Sulmona, Italy
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