JAMB Chemistry 1999 Question 12

Question 12

Water

The method that can be used to convert hard water to soft water is

A.chlorination
B.passage over activated charcoal
C.the use of an ion-exchange resin
D.aeration

Show the answer and explanation

Answer: C (the use of an ion-exchange resin)

Explanation

An ion-exchange resin swaps the Ca²⁺ and Mg²⁺ ions that cause hardness for Na⁺ ions, softening the water. Chlorination and charcoal treat germs and odours, not hardness.