Answer: 0.4mL of the stock solution is needed
Explanation:
This is simply a dilution analysis. From the question, the following were obtained:
C1 = 25 mg/mL = 25x10^-3g/mL
V1 =?
C2 = 25 ug/mL = 25x10^-6g/mL
V2 = 400ml
Applying the dilution formula, we have:
C1V1 = C2V2
25x10^-3 x V1 = 25x10^-6 x 400
Divide both side by 25x10^-3, we have:
V1 = (25x10^-6 x 400) / 25x10^-3
V1 = 0.4mL
Therefore, 0.4mL of the stock solution need.
