Basis of differentiation | Molarity | Osmolarity |
Definition | The concentration of a solute in a solution, expressed as the number of moles of solute per liter of solution | The concentration of all osmotically active particles in a solution, expressed as the number of osmoles (or milliosmoles) of solute per liter of solution |
Units | mol/L (molar) | osmol/L (osmolar) or mOsmol/L (milliosmolar) |
Dilution factor | Molarity changes upon dilution but the total number of moles of solute remains constant | Diluting a solution involves adding more solvent, which increases the total volume and decreases the concentration, while the amount of solute remains constant |
Components | Involves only the number of moles of solute present | Involves all particles that contribute to osmotic pressure, including ions and molecules |