Question on Molarity

What is the molar concentration of water?

Answer:

Molar concentration is the number of moles of the solute present in one litre of the solution. Taking the density of water to be 1g/mL, we can say that 1000mL of water weighs 1000g. 1000g of water has (1000/18) = 55.56 moles of water. Thus 1L of water contains 55.56 moles of it. So, the molar concentration of water is 55.56M.