what is the molarity of a 25 ml sample if it is diluted by adding 50 mol pf water and the molarity changes to 0.186 m?

0.558 M

Explanation:

Data obtained from the question. This includes the following:

Initial concentration (C1) = ... ?

Initial volume (V1) = 25mL

Final volume = 25 + 50 = 75mL

Final concentration (C2) = 0.186 M

The initial concentration of the solution can be obtained as follow:

C1V1 = C2V2

C1 x 25 = 0.186 x 75

Divide both side by 25

C1 = (0.186 x 75) / 25

C1 = 0.558 M

Therefore, the initial concentration of the stock was 0.558 M