Question

The following can convert hard water into soft water :

• A. $HCl$
• B. $H_2{O}_2$
• C. Lead nitrate
• D. Sodium aluminium silicate

Answer 1

Answer: (D)

Sodium aluminium silicate

The hardness of water is due to carbonate or sulphate of $C{a}^{2+}$ and $M{g}^{2+}$ ions. When sodium aluminum silicate is added $N{a}^{+}$ replaces $C{a}^{2+}$ and $M{g}^{2+}$ by adsorption, and hence water becomes soft.

$Hencethecorrectanswerisoption\left(D\right)$