Question

(b) 25 ml of waste water was diluted to 500 ml and equal volumes are filled in two BOD bottles. In the blank titration, 100 ml of diluted waste water when titrated immediately required 6.1 ml of 0.02 N Na 2 S 2 O 3 solution. 100 ml of the incubated sample after 5 days required 3.6 ml of same Na 2 S 2 O 3 solution. Calculate BOD of waste water.

Answer 1

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