What is the initial concentration of crystal violet solution

Question

What is the initial concentration of crystal violet solution made from adding 4.04 mL of 1.00x10^-5 M CV solution to 3.00 mL of 0.100M NaOH(aq) and diluting with water to make a 25.00 mL solution? Report your answer in μM.

Answer 1

The final concentration of CV is what we'd be looking for. This simple dilution takes 4.04 mL of 1.00 x 10^-5 M CV and diluting it to 25 mL (final volume).

V₁M₁ = V₂M₂

V₁ (initial volume) = 4.04 ml

V₂ (final volume) = 25.0 ml

M₁ (initial molarity) = 1.00x10^-5 M

M₂ (final molarity) = x

(4.04 mL)(1.00x10^-5 M) = (25.0 mL)(x M)

x = 1.616 · 10^-6 M

M --> uM = 1.62 nM

The initial concentration of CV in uM:

1.00 · 10^-5 M · 1 uM / 1 · 10^-6 M = 10 uM