ANS:D - all (a), (b) and (c).

Certainly! Let's go through each option: a) Lowering of vapor pressure: This statement is a part of Raoult's Law, which describes the relationship between the vapor pressure of a solution and the mole fraction of the solvent. According to Raoult's Law, the vapor pressure of a solution is lower than that of the pure solvent, and the extent of lowering is directly proportional to the mole fraction of the solute. However, this is specifically related to the colligative property of vapor pressure lowering, not osmotic pressure. b) Molecular concentration of the solute: Osmotic pressure is indeed directly proportional to the molecular concentration of the solute. This is a fundamental principle described by van't Hoff's Law, which states that the osmotic pressure (ΠΠ) of a solution is proportional to the concentration of the solute particles (in moles per unit volume) and the absolute temperature (𝑇T). Π=𝑖⋅𝑀⋅𝑅⋅𝑇Π=i⋅M⋅R⋅T Where:

• ΠΠ is the osmotic pressure,
• 𝑖i is the van't Hoff factor (the number of particles into which the solute dissociates),
• 𝑀M is the molarity of the solution,
• 𝑅R is the ideal gas constant, and
• 𝑇T is the absolute temperature.

c) Absolute temperature of a given concentration: The osmotic pressure of a solution is directly proportional to the absolute temperature when the concentration of the solute remains constant. This relationship is evident from van't Hoff's Law, where 𝑇T appears directly in the equation, indicating that as temperature increases, the osmotic pressure also increases, assuming other factors remain constant. So, the correct statement is: all (a), (b), and (c).