Question

calculate the volume of solvent required to prepare 20% by volume (v/v) solution using 70 ml of H2So4

Answer 1

by using the volume percentage formula
V/V%=volume of solvent by volume of solvent + volume of solution × 100
volume of solution is 70 ml
V/V%=20%
here volume of solvent we need find
20=V/V+70×50 by solving this we get volume of solute =15 ml

Answer 2

The volume of solvent required to prepare 20% by volume (v/v) solution using 70 mL of H2SO4 is 280 mL

Given,

volume percent of the solution = 20%

volume of H2SO4 = 70 mL

To Find,

The volume of solvent required

Solution,

This could be found by using the volume percent formula

The volume percent formula is given as follows:

$\frac{v}{v} \% = \frac{volume \hspace{0.1 cm} of \hspace{0.1cm} solute}{volume \hspace{0.1 cm} of \hspace{0.1cm} solution} \times 100 \%$

This can also be written as follows:

$\frac{v}{v} \% = \frac{volume \hspace{0.1 cm} of \hspace{0.1cm} solute}{volume \hspace{0.1 cm} of \hspace{0.1cm} solute \hspace{0.1cm} + \hspace{0.1cm} volume \hspace{0.1 cm} of \hspace{0.1cm} solvent} \times 100 \%$

We have been given the volume percent = 20 %

also, the volume of solute = volume of H2SO4 = 70 mL

We have to find the volume of solvent. Let it be 'x'

Therefore, substituting values in the above formula for volume percent, we get the following equation:

$20 = \frac{70}{70 \hspace{0.1cm} + \hspace{0.1cm} x} \times 100$

$\frac{20}{100} = \frac{70}{70 \hspace{0.1cm} + \hspace{0.1cm} x}$

$\frac{1}{5} = \frac{70}{70 \hspace{0.1cm} + \hspace{0.1cm} x}$

$70\hspace{0.1cm}+\hspace{0.1cm}x = 70\times5$

$70\hspace{0.1cm}+\hspace{0.1cm}x = 350$

$x = 350-70$

$x=280\hspace{0.1cm}mL$

Therefore, the volume of solvent required to prepare 20% by volume (v/v) solution using 70 mL of H2SO4 is 280 mL

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