Q. Alum helps in purifying water by :
A) Forming Si complex with clay particles
B) Sulphate part which combines with the dirt and removes it
C) Aluminium which coagulates the mud particles
D) Making mud water soluble
Explanation
(c)
$Al^{3 +}$ is very good coagulating agent for ⎯ve sol (muddy water).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.