Answer: Thus 167 ml of a 0.75M solution is needed to make 500 mL of a 0.25M solution
Step-by-step explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.
According to the dilution law,

where,
= molarity of concentrated solution = 0.75 M
= volume of concentrated solution = ?
= concentration of dilute solution= 0.25 M
= volume of dilute solution= 500 ml
Putting in the values we get:


Thus 167 ml of a 0.75M solution is needed to make 500 mL of a 0.25M solution