199. The concentration of calcium and magnesium ions ($\text{X}^{2+}$) in a hard water sample is 0.0025 molar and 264 ppm, respectively. If 27 grams of solid soap with a molar mass of $300\ \text{g.mol}^{-1}$ is added to 2.5 liters of this water sample, and considering that soap loses its cleaning ability by reacting with hard water ions and these $\text{Na}^+(\text{aq})$ ions exchange with $\text{Na}^+(\text{aq})$ ions, approximately how many grams of $\text{Na}^+(\text{aq})$ are needed in this process? (The mass of one gram per milliliter of water is considered from this sample.) $(Na = 23, Mg = 24 : \text{g.mol}^{-1})$ (Balanced reaction equation: $\text{RCOONa} + \text{XCl}_\gamma \rightarrow (\text{RCOO})_\gamma\text{X} + \text{NaCl}$) (1) 0.78 , 75 (2) 1.55 , 75 (3) 1.55 , 25 (4) 0.78 , 25
\textbf{199.} The concentration of calcium and magnesium ions ($\text{X}^{2+}$) in a hard water sample is 0.0025 molar and 264 ppm, respectively. If 27 grams of solid soap with a molar mass of $300\ \text{g.mol}^{-1}$ is added to 2.5 liters of this water sample, and considering that soap loses its cleaning ability by reacting with hard water ions and these $\text{Na}^+(\text{aq})$ ions exchange with $\text{Na}^+(\text{aq})$ ions, approximately how many grams of $\text{Na}^+(\text{aq})$ are needed in this process? (The mass of one gram per milliliter of water is considered from this sample.)\\
$(Na = 23, Mg = 24 : \text{g.mol}^{-1})$
(Balanced reaction equation: $\text{RCOONa} + \text{XCl}_\gamma \rightarrow (\text{RCOO})_\gamma\text{X} + \text{NaCl}$)
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(1) 0.78 , 75 \qquad (2) 1.55 , 75 \qquad (3) 1.55 , 25 \qquad (4) 0.78 , 25
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