Given below are two statements : Statement I : H_2O molecules move from the chamber 1 to chamber 2. Statement II : The osmotic pressure of a solution prepared by dissolving 50 mg of potassium sulphate (molar mass = 174 g/mol) in 2 L of water (at 27°C) is 0.0107 bar. (Given : R = 0.083 dm^3 bar K^ -1 mol^ -1 and assume complete dissociation of electrolyte) In the light of the above statements, choose the correct answer from the options given below :
D. Statement I is false but Statement II is true
For Statement I: Molarity of the solution in Chamber 1 (M_1) = 18 / 180 100 / 1000 = 1 M Molarity of the solution in Chamber 2 (M_2) = 30 / 180 250 / 1000 = 1/6 1/4 = 0.667 M Since M_1 > M_2, the solution in Chamber 1 has a higher solute concentration. During osmosis, the solvent (water) moves from the region of lower solute concentration to the region of higher solute concentration across a semi-permeable membrane. Thus, water will move from Chamber 2 to Chamber 1. Statement I is false. For Statement II: The osmotic pressure is given by = iCRT For K_2SO_4, assuming complete dissociation (K_2SO_4 2K^+ + SO_4^ 2- ), the van't Hoff factor i = 3. Concentration C = 50 10^ -3 174 2 mol/L = 3 ( 50 10^ -3 174 2 ) 0.083 300 = 3 0.05 24.9 348 = 3.735 348 0.0107 bar Statement II is true. Therefore, Statement I is false but Statement II is true. Answer: Statement I is false but Statement II is true
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