Answer: V = 16.25 mL
Explanation: The dilution formula is expressed by the products of molarity and volume or M1V1 = M2V2. Derive the formula to find the initial volume.
V1 = M2V2 / M1
= 0.65 M ( 150 mL ) / 6.0 M
= 16.25 mL
Cancel out the units of molarity so that the remaining unit is in mL.