Question

What is the final volume V2 in milliliters when 0.646 L of a 30.5 % (m/v) solution is diluted to 23.5 % (m/v)? Express your answer with the appropriate units.

Answer 1

Let us assume the molar mass of solute be Y.

Converting the % (m/v) to Molarity:

30.5%(m/v) solution means 30.5 g of solute in 100 ml of solution.

Molarity = (mass of solute / molar mass of solute) / Volume of solution in litres

M₁ = (30.5/Y)/0.1 = (3.05/Y) M

23.5%(m/v) solution means 23.5 g of solute in 100 ml of solution.

M₂ = (23.5/Y)/0.1 = (2.35/Y) M

Applying law of dilution,

M₁ V₁ = M₂ V₂

(3.05/Y) 0.646 = (2.35/Y) V₂

V₂ = 3.05 0.646 /2.35 = 0.8384 L = 838.4 mL