Explanation: %(m/v) stands for mass by volume percentage. 2.5%(m/v) means 2.5 grams of a solute present in 100 mL of a solution.

The question asks to calculate the volume of 2.5%(m/v) KOH solution that can be prepared from 125 mL of a 5.0%(m/v) KOH solution.

It’s a dilution problem and could easily be solved by using dilution equation:

[tex]C_1V_1=C_2V_2[/tex]

where [tex]C_1[/tex] is the concentration before dilution and [tex]C_2[/tex] is the concentration after dilution. Similarly, [tex]V_1[/tex] is the volume before dilution and [tex]V_2[/tex] is the volume after dilution.

Let’s plug in the values in the equation:

[tex]5.0(125mL)=2.5(V_2)[/tex]

[tex]V_2=frac{5.0(125mL)}{2.5}[/tex]

[tex]V_2[/tex] = 250 mL

So, 250 mL of 2.5%(m/v) KOH solution can be prepared from 125 mL of 5.0%(m/v) KOH solution.

## Answers ( 2 )

Answer: 250 mLExplanation: %(m/v) stands for mass by volume percentage. 2.5%(m/v) means 2.5 grams of a solute present in 100 mL of a solution.The question asks to calculate the volume of 2.5%(m/v) KOH solution that can be prepared from 125 mL of a 5.0%(m/v) KOH solution.

It’s a dilution problem and could easily be solved by using dilution equation:

[tex]C_1V_1=C_2V_2[/tex]

where [tex]C_1[/tex] is the concentration before dilution and [tex]C_2[/tex] is the concentration after dilution. Similarly, [tex]V_1[/tex] is the volume before dilution and [tex]V_2[/tex] is the volume after dilution.

Let’s plug in the values in the equation:

[tex]5.0(125mL)=2.5(V_2)[/tex]

[tex]V_2=frac{5.0(125mL)}{2.5}[/tex]

[tex]V_2[/tex] = 250 mL

So, 250 mL of 2.5%(m/v) KOH solution can be prepared from 125 mL of 5.0%(m/v) KOH solution.the volume of 2.5% m/v koh which can prepared from 125 ml of a 5% koh solution is calculated using the following formula

m1v1= m2 v2

M1= 5/100= 0.05

v1= 125

m2=2.5/100=0.025

V2=?

v2= m1v1/m2

=

0.05 x125 /0.025=250 ml