228 – To $200\,\text{mL}$ of hard water $(d = 1\,\text{g.mL}^{-1})$ containing $\text{Ca}^{2+}$ ions at a concentration of $2000\,\text{ppm}$, $4.72$ grams of soap with molar mass $236\,\text{g.mol}^{-1}$ is added. Assuming the reaction of soap with calcium ions is complete, what percentage of it precipitates? $(Ca = 40,\ Na = 23\ ;\ \text{g.mol}^{-1})$ (The balanced equation is: $\text{RCOONa(aq)} + \text{CaCl}_2\text{(aq)} \rightarrow (\text{RCOO})_2\text{Ca(s)} + \text{NaCl(aq)}$) (1) $15$ (2) $20$ (3) $50$ (4) $100$
\textbf{228 –} To $200\,\text{mL}$ of hard water $(d = 1\,\text{g.mL}^{-1})$ containing $\text{Ca}^{2+}$ ions at a concentration of $2000\,\text{ppm}$, $4.72$ grams of soap with molar mass $236\,\text{g.mol}^{-1}$ is added. Assuming the reaction of soap with calcium ions is complete, what percentage of it precipitates?
$(Ca = 40,\ Na = 23\ ;\ \text{g.mol}^{-1})$
(The balanced equation is: $\text{RCOONa(aq)} + \text{CaCl}_2\text{(aq)} \rightarrow (\text{RCOO})_2\text{Ca(s)} + \text{NaCl(aq)}$)
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(1) $15$ \hfill (2) $20$ \hfill (3) $50$ \hfill (4) $100$
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