Which process for making water safe to drink involves adding alum to clump impurities? A. aeration B. disinfection C. filtration D. coagulation

The correct option is D) coagulation

Explanation:

Aluminium sulfate is commonly known as alum. Alum serves as a flocculant. Unprocessed water contains such contaminants which are very tiny and cannot be trapped by filtration. Alum or aluminium sulfate causes these particles to coagulate and form clumps hence, causing their size to increase due to which they can now be trapped in the filter. Coagulation also removes tiny bacteria from the raw water. Hence, option D is correct.

filtration