After incubation at 20 c, calculate the value of BOD5 in mg o2/L using manometer for 432 ml of water sample that has been taken from moderately polluted river. if the volume of the umber bottle is 500ml and the reading from the cap was 30, where R is 0.082 L. atm/ k. mol note ; 1 mole of O2 is equal to 32 gm​