The molar mass of the solute sodium hydroxide obtained from the measurement of osmotic pressure of its aqueous solution at 270C is 25g mol–1. Therefore its ionization percentage in this solution is

Molar mass of NaOH determined by Osmotic pressure measured = 25g/mole% of ionization of NaOH = ?van'thoff factor (i) = Normalmolecular Wt observed mol.wt. =4025=1.6NaOH⇌Na++OH- n=2i=1-α+nαi =1-α+2α1.6 = 1+α      α= 0.6% of ionization =0.6X100=60%