Answer:
3.125 mL
Step-by-step explanation:
The following data were obtained from the question:
Molarity of stock solution (M1) = 12 M
Molarity of diluted solution (M2) = 0.250 M
Volume of diluted solution (V2) = 150 mL
Volume of stock solution needed (V1) =.?
The volume of stock solution needed can be obtained by using the dilution formula as shown below:
M1V1 = M2V2
12 × V1 = 0.250 × 150
12 × V1 = 37.5
Divide both side by 12
V2 = 37.5/12
V2 = 3.125 mL
Therefore, the volume of the stock solution needed is 3.125 mL