Question

Hard water is not fit for washing clothes because:

• A. it contains impurities
• B. it is acidic in nature
• C. it gives precipitate with soap
• D. it contains $N{a}_{2}S{O}_4$ and $KCl$

Answer 1

Answer: (C)

Hard water contains dissolved salts of calcium, magnesium or iron, which form insoluble precipitate with soap. $\underset{Soap}{2RCOONa}+C{a}^{2+}\to \underset{\text{Insoluble}}{{(RCOO)}_{2}Ca}+2N{a}^{+}$