Calculate the volume, in ml. of the 1.0 m naoh stock solution needed to prepare 250 ml of 0.1 molar naoh.

By using the following formula we can calculate the volume;

C₁V₁ = C₂V₂

C₁ = concentration of starting solution = 1.0m

V₁ = volume of starting solution that is needed to make the dilution = ?

C₂ = Desired concentration of final solution = 0.1m

V₂ = desired volume of final solution = 250ml

Now putting the values in the formula;

1 x V₁ = 0.1 x 250

V₁ = 25ml

Thus, the answer is 25ml.