The concentration unit molarity may be expressed with the units of moles solute per liter of solution. What is a solute, a solvent, and how does a solution differ from a solvent?
A solution is the result of the solvent dissolving the solute so there is at least one more substance in the solution than there was in the original solvent.
Pepsi is an example of solution. The solvent was water. There are several solutes in the solution, sugar, Carbon Dioxide, coloring, and flavoring.
Sometimes determining which substance is the solvent and which is the solute is somewhat arbitrary. Such as a solution made of Alcohol and water. The proportions of the solution can range from 1% alcohol to 95 % alcohol. Water is generally consider to be the solvent but at 95% concentration alcohol could as easily be considered to be the substance doing the dissolving.