For water, the molal elevation constant Kb=0.52 K kg mol−1 and the molal depression constant Kf=1.86 K kg mol−1. Thus, Kb<Kf. Statement A is incorrect.
For a solution with a given molality m of a non-volatile solute, the elevation in boiling point is ΔTb=Kbm and the depression in freezing point is ΔTf=Kfm. Since Kb<Kf, it follows that ΔTb<ΔTf. Statement B is incorrect.
Osmotic pressure measurement is preferred for determining the molar mass of macromolecules such as proteins and polymers because the measurement is done at room temperature and the magnitude of osmotic pressure is significant even for very dilute solutions. Statement C is correct.
In benzene, benzoic acid undergoes dimerization through intermolecular hydrogen bonding, forming a cyclic dimer with two hydrogen bonds. The structure given in statement D represents a linear association with only one hydrogen bond. Statement D is incorrect.
Therefore, statements A, B, and D are incorrect.
Answer: A, B and D only