Calculate the molarity of pure water $(\mathrm{d}=1\mathrm{g}/\mathrm{ml})$

Calculate the Molarity of Pure Water

To determine the molarity of pure water, we follow these steps:

1. Assume the volume of water:
   Let's consider 1000 ml (1 litre) of pure water.
2. Calculate the mass of water:
   Since the density of water (d) is 1 g/ml, the mass of 1000 ml of water is:
   Mass = Volume × Density = 1000 ml × 1 g/ml = 1000 grams
3. Find the number of moles of water:
   The molecular mass of water (H₂O) is 18 g/mol. The number of moles is calculated as:
   Number of moles = Mass / Molecular Mass = 1000 g / 18 g/mol = 55.5 moles
4. Calculate the molarity:
   Molarity is defined as the number of moles of solute per litre of solution. In this case, the volume is 1 litre:
   Molarity = Number of moles / Volume (in litres) = 55.5 moles / 1 litre = 55.5 M

Thus, the molarity of pure water is 55.5 M.