A solution was diluted 1/40, and the final concentration was 20%. What was the original concentration?

The original concentration : 800%

Given

Diluted 1/40

Final concentration 20%

Required

The original concentration

Solution

Dilution is the process of adding solvent to get a more dilute solution.

The moles(n) before and after dilution are the same.

Can be formulated :

 n₁ = n₂

M₁.V₁ = M₂.V₂

diluted 1/40(dilution factor)⇒ V₁/V₂=1/40⇒V₂/V₁=40

M₂ = 0.2(20%)

Input the value for M₁ :

M₁=M₂ x (V₂/V₁)

M₁ = 0.2 x 40

M₂ = 8(800%)

=