The osmotic pressure of a phenol solution in an organic solvent is determined to be 20% less than expected, it is due to

phenol  dissolved in organic solvent showed 20% lesser osmotic pressure than expectedI) phenol is 20% ionized ; can never be trueBecause on ionization no.of particles increases and i>12) If phenol dimerises, n=2For solute undergoing association in any solvent,So  40% phenol  dimerises