Question

Which of the following is not a hard water.

• A. Water containing $CaCl_{2}$
• B. Water containing dil. HCl
• C. Water containing $MgSO_{4}$
• D. None of these

Answer 1

Answer: (D)

None of these

Answer 2

Water containing $Ca^{+ 2},\mspace{6mu} Mg^{+ 2}$ and $H^{+}( > 10^{- 7}m)$ is a hard water.

$H^{+}(aq) + CH_{3}COONa(aq)$ ⇌ $CH_{3}COOH(s) + Na^{+}(aq)$