Class 12 chemistry PYQ solution chapter

Q4: The following solutions were prepared by dissolving 10g of glucose (C₆H₁₂O₆) in 250 ml of water (P1). 10g of urea (CH₄N₂O) in 250 ml of water (P₂) and 10 g of sucrose (C₁₂H₂₂O₁₁) in 250 ml of water (P₃). The decreasing order of osmotic pressure of these solutions is:      (NEET 2021)

(a) P₂ > P₃ > P₁
(b) P₃ > P₁ > P₂
(c) P₂ > P₁ > P₃
(d) P₁ > P₂ > P₃ 

Ans: (c)

                           

Explanation video in tamil language

.         Osmotic pressure (π) = iCRT where C is molar concentration of the solution 

·      With increase in molar concentration of solution osmotic pressure increases.

.     Since, weight of all solutes and its solution volume are equal, so higher will be the molar mass of   solute,smaller will be molar concentration and smaller will be the osmotic pressure.

·      Order of molar mass of solute decreases as Sucrose > Glucose > Urea

·     So, correct order of osmotic pressure of solution is P₃ > P₁ > P₂