Question

What quantity of a 30% solution do you need to make 150 mL of a 20% solution?

A. 100 mL
B. 50 mL
C. 150 mL
D. 200 mL

Answer 1

Volume required = 100mL

Explanation:

Let the volume of 30% solution required be = V mL

Amount of solute in V mL of solution = 30% of V = 0.3V...............(i)

This amount is also present in 150 mL of 20% solution

For 150 mL of 20% solution we have amount of solute = 150 mL X 20%

= 30..............(ii)

Thus equating i and ii we get

0.3V = 30

Thus V =100 mL