Question

Which of the following will cause softening of hard water.

• A. Passing it through cation exchange resin
• B. Passing it through anion exchange resin
• C. Passing it through sand
• D. Passing it through alumina

Answer 1

Answer: (A)

Passing it through cation exchange resin

Answer 2

In cation exchange resin $Mg^{+ 2}$ and $Ca^{+ 2}$ (cations) are replaced by $Na^{+}$ ions.