What is the significance of molecular formula

The molecular formula of a compound represents molecular mass of the substance. For example, the molecular mass of water molecule (H2O) is 18u.

(iv) The molecular formula of any compound gives the name, and actual number of atoms of each kind present in one molecule of the substance. For example, the formula for water is H2O. This means that every molecule of water is made up of 2 atoms of hydrogen and one atom of oxygen.