0.03192 M
We are given;
We are required to calculate the initial concentration, M1 before dilution.
Rearranging the formula;
M1 = M2V2 ÷ V1
= ( 0.00383 M × 0.125 L) ÷ 0.015 L
= 0.03192 M
Therefore, the original concentration of the solution before dilution is 0.03192 M