UPSC Civil Service Exam Questions - Engineering

Q1:

Consider the following statements :
1. Alum coagulation decreases the alkalinity of water.
2. Alum coagulation increases permanent hardness of water.
3. Alum coagulation decreases pH of water.
4. Alum coagulation produces aluminium hydroxide flocks in the flocculation process.
Which of the statements given above are correct ?

A 1, 2, 3 and 4

B 1, 3 and 4 only

C 1 and 2 only

D 2, 3 and 4 only

ANS:A - 1, 2, 3 and 4

Alum also increade the permanent hardness of water.