Determination of HNO3 concentration:
5 ml of bath solution sample and 5 grams of potasium flouride are added to 100 ml distilled water in an erlenmayer flask. 3-4 drops of phenol phytalein indicator is added to this mixture and titrate 1.0 N NaOH solution until colour changes to pink .ml of 1,0 N NaOH solution is consumed during titration is recorded as “A”.
Nitric acid concentration : 100-150 g/l
Temperature : Room temperature
Treatment time : 1-4 minutes