What will be the molarity of pure water?

Molarity is defined as the number of moles of solute per liter of solution. For pure water, since it is not a solution with a separate solute, we consider water itself to be the solvent. To calculate the molarity of pure water, we need to treat the mass of water as the solute.

• The molar mass of water (H₂O) is 18 g/mol.
• 1 liter of water weighs approximately 1000 grams.

To find the molarity, divide the number of moles of water by the volume in liters:$\frac{1000\left(\text{ volume in }\mathrm{mL}\right)}{18\left(\text{ molar mass }\right)}=55.6$