Answer:
41 ml of the 0.15 solution should be diluted with 84 ml of water to prepare 125.0 ml of a 0.050 M solution
Explanation:
since the final solution has 0.050M , the amount of moles that should be present in 125 ml are
amount of moles = molarity * volume
amount of moles = 0.050 moles/L * 0.125L = 6.25*10⁻³ moles
therefore for a solution 0.15 M
amount of moles = molarity * volume
6.25*10⁻³ moles = 0.15 M*volume
volume = 0.041 L = 41 ml
if the number of moles are contained in 41 ml , the rest should be solvent ( water)
amount of water to dilute = 125 ml - 41 ml = 84 ml
then we will have 6.25*10⁻³ moles in 125 ml
