Comsidering the definition of dilution, 7.5 mL of the stock solution of 2 M are required to prepare 100 mL of 0.150 M solution.
Dilution is a procedure by which the concentration of a solution is lowered. It is achieved by adding more solvent to the same amount of solute.
Then the amount of solute does not vary, but the volume of the solvent does: when more solvent is added, the concentration of the solute decreases, as the volume of the solution increases.
A dilution is mathematically expressed as:
Ci×Vi = Cf×Vf
where
In this case, you know:
Replacing in the definition of dilution:
2 M×Vi= 0.150 M×100 mL
Solving:
[tex]Vi=\frac{0.150 M x 100 mL}{2 M}[/tex]
Vi= 7.5 mL
In summary, 7.5 mL of the stock solution of 2 M are required to prepare 100 mL of 0.150 M solution.
Learn more about dilution:
