The dissolution of 7.75g of a substance in 825 g of benzene at 298 K raises the boiling point by 0.575°C. Note that K _f = 5.12 K kg mol^–1, K_b = 2.53 K kg mol^–1, and the density of benzene is 876.6 kg m^–3. Calculate the freezing point depression, the ratio of the vapor pressure above the solution to that of the pure solvent, the osmotic pressure, and the molecular weight of the solute.  P= _benzene = 10³ Torr at 298 K.