0.2g of a substance A dissolved …

According to the question it is given that Osmotic pressure of A and B are equal therefore let us assume that the pressure of to be π Since the osmotic pressure for both A and B are equal then the temperature will also be equal and let it be T. Now, we know that , π = CRT = amount of solute x RT/ mass. of solute x volume of solution Mass of solute = amount of solute x RT / πV Case 1 : We have , amount of solute, w = 0.2 amount of solvent, w'= 200 ml = 0.2 L Now, Molecular mass of A = 0.2 RT / 0.2 π = RT/π Case 2 : We have, amount of solvent , w = 0.3 g amount of solvent, w'= 200 ml = 0.2 L Now, Molecular mass of B = 0.3RT/0.2π = 1.5 Rt /π Thus, molecular mass of A < Molecular mass of B