Question

Ramlal adds alum to the water stored in his house. How does this help?
(a) Alum dissolves the impurities in water.
(b) Alum causes the impurities to stick to it and settle down.
(c) Alum makes the impurities lighter so that they can float on water and can then be removed easily.
(d) On adding alum, the impurities become harmless.

Answer 1

(b) Alum causes the impurities to stick to it and settle down
The impurities stick to alum because of which they become heavier and settle down.