Chapter 14, Problem 112A

Interpretation Introduction

Interpretation:

Both the amount of solute and solvent have to be calculated.

Concept introduction:

Volume/volume percentage (v/V percent): Percent by volume can bedefined as the ratio of the volume of the solute to the total volume of the solution multiplied by 100. This is used when both chemicals in a solution are liquid.

In expression,

$Percentbyvolume\left(v/V\right)\%ofacomponent=\frac{Volumeof the solute}{Total volume of the solution}\times 100$

Answer to Problem 112A

50 mL HCl needed to prepare 1000 mL of 5% HCl solution. To calculate the amount of solvent, amount of HCl have to be subtracted from the total solution. So, the volume of H₂O is 950 mL. 50 mL HCl have to dissolve in somewhat less than 950 mL H₂O and have to add more water until total volume of the solution becomes 1000 mL.

Explanation of Solution

Given information:

Percent by volume of HCl = 5%

Total volume of the solution = 1000 mL

Write the expression for percent of volume of $\mathrm{HCl}$.

$\begin{array}{l}PercentbyvolumeofHCl=\frac{Volumeof thesolute(HCl)}{Total volume of HCl solution}\times 100\\ Volumeof thesolute(HCl)=\frac{PercentbyvolumeofHCl\times Total volume of the solution}{100}\\ =\frac{5\times 1000mL}{100}=50mL\end{array}$

Volume of the solute (HCl) = 50 mL

Volume of the solvent (water) = (1000 - 50) mL = 950 mL