6.The alum, when added as a coagulant in water

7.If the total hardness of water is greater than its total alkalinity, the carbonate hardness will be equal to

8.The effective size of sand particles used in slow sand filters is

9.The amount of coagulant needed for coagulation of water increases with i) increase in turbidity of water ii) decrease in turbidity of water iii) increase in temperature of water iv) decrease in temperature of water The correct answer is

10.In water treatment, rapid gravity filters are adopted to remove