What is the concentration of a dextrose solution prepared by diluting 19 ml of a 4.0 m dextrose solution to 25 ml using a 25 ml volumetric flask?

3.04 M

Explanation:

Dilution is the process of decreasing the concentration of a solute in a solution, usually simply by mixing with more solvent like adding more water to a solution. To dilute a solution means to add more solvent without the addition of more solute.

When a solution of given molarity  and volume is diluted its new concentration can be found using the formulae :

in the given problem

so upon substituting thse values in the above equation we get our resulting concentration to be 3.04 M