What is the percent by volume of ethanol in the solution? 60 mL of ethanol is diluted with water to a final volume of 400 mL.
If 60 ml of ethanol is diluted to a final volume of 400 ml, you create a 35 % ethanol solution.
If you pour 60 ml of ethanol in a volumetric flask, you add 340 ml of water to dilute this solution to a final volume of 400 ml.
Volumetric flasks are designed to make or dilute solutions to specified final volume.
Since you have 60 ml of ethanol in a total solution of 400 ml, the percentage of ethanol is 35 %.
This result is obtained in the following manner.
- ml/400. ml. = .35
.35 x 100% = 35 %