e. The factor of converting the concentration of CO32 from "as ion" to "as CaCO3 " is (i) 2.18 (ii) 0.82 (iii) 1.04 (iv) 1.67 f. Which of the following is used as a chemical coagulant? (i) calcium chloride (ii) alum (iii) lime (iv) soda ash g. In determining the proper dosage of alum, the most useful test is the test: (i) hardenss (ii) jar (iii) carbonate (iv) pH h. Carbon dioxide is used in water treatment to do what? (i) disinfect (ii) raise pH (iii) lower pH (iv) stabilize ammonia compounds i. A method used to soften water is (i) aeration (ii) sedimentation (iii) ion exchange (iv) adsorpti