Question

Question #f5fb2

Answer 1

You must use 46 mL of the concentrated `"HCl"`.

Explanation:

You can use the dilution formula

`color(blue)(bar(ul(|color(white)(a/a)c_1V_1 = c_2V_2color(white)(a/a)|)))" "`

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`

Your data are:

`c_1 = "10.0 mol/L"; V_1 = "?"`
`c_2 = "2.0 mol/L"; color(white)(ll)V_2 = "231 mL"`

`V_1 = "231 mL" × (2.0 color(red)(cancel(color(black)("mol/L"))))/(10.0 color(red)(cancel(color(black)("mol/L")))) = "46 mL"`