(a) what do you understand by dissolved oxygen in water. How does it create table in boilers? Give chemical methods with suitable reactions to remove it from the water.
(b) write phosphate conditioning method for water softening with suitable chemical reactions. How is it different from soda lime method.
(c) a sample of water analysis was found to contain temporary magnesium hardness 25 mg/l. Permanent magnesium chloride hardness 15 mg/l and permanent calcium sulphate hardness 20 mg/l, SiO2= 30kg/l. calculate the lime and soda required for softning 30000 litres hard water.