# Question f5fb2

Jun 18, 2017

You must use 46 mL of the concentrated $\text{HCl}$.

#### Explanation:

You can use the dilution formula

$\textcolor{b l u e}{\overline{\underline{| \textcolor{w h i t e}{\frac{a}{a}} {c}_{1} {V}_{1} = {c}_{2} {V}_{2} \textcolor{w h i t e}{\frac{a}{a}} |}}} \text{ }$

where ${c}_{1}$ and ${c}_{2}$ are the concentrations and ${V}_{1}$ and ${V}_{2}$ are the volumes.

You can rearrange this formula to get

V_1 = V_2 × c_2/c_1#

${c}_{1} = \text{10.0 mol/L"; V_1 = "?}$
${c}_{2} = \text{2.0 mol/L"; color(white)(ll)V_2 = "231 mL}$
${V}_{1} = \text{231 mL" × (2.0 color(red)(cancel(color(black)("mol/L"))))/(10.0 color(red)(cancel(color(black)("mol/L")))) = "46 mL}$