Question

Which of the following is not a disadvantage of using hard water?

• A. In production of steam in boilers
• B. Formation of scales in cooking utensils
• C. In cooking,bathing and washing
• D. In ion exchanges

Answer 1

The correct option is D In ion exchanges

In an ion exchange using hard water is not a disadvantage since it becomes soft by exchanging anions or cations. $N{a}^{+}$, $C{a}^{2+}$ and $M{g}^{2+}$ ions (from water) are exchanged with $H^{+}$ ions (from cation exchange resins). $C{l}^{-}$, $S{O}_4^{2-}$ and $N{O}_3^{-}$ ions (from water) are exchanged with $O{H}^{-}$ ions (from anion exchange resins).