Molarity, also known as concentration in amount of matter, is the ratio between the amount of solute matter, measured in mol (n1), and the volume of solution in liters (V). This concentration is measured in mol per liter (mol / L). It is often called by some authors molar concentration, but the correct terms are "concentration in mol / L" or "concentration in amount of matter".
Consider the gastric juice that our stomach produces for the purpose of performing the digestion process. In fact, it is a hydrochloric acid (HCl) solution at a concentration of 0.01 mol / L. This means that for every liter of gastric juice there is 0.01 mol HCl. The same goes for basic concentration solutions. Consider a NaOH solution at a concentration of 0.02 mol NaOh. This means that if each NaOh litter is present, there is 0.02 mol of NaOh.