Question

Which one of the following statements is false?

• A. Raoulfs law states that the vapour pressure of a component over a solution is proportional to its mole fraction
• B. The osmotic pressure $ (\pi ) $ of a solution is given by the equation $ \pi =MRT, $ where M is the molarity of the solution
• C. The correct order of osmotic pressure for 0.01 M aqueous solution of each compound is $ BaC{{l}_{2}}>KC1>C{{H}_{3}}COOH>sucrose $
• D. Two sucrose solutions of same molality prepared in different solvents will have the same freezing point depression

Answer 1

Answer: (D)

(a) $ {{p}_{A}}={{X}_{A}}P_{A}^{o} $ true (b) $ \pi =iMRT=MRT $ true (if vant Hoff factor $ i=1 $ ) (c) $ i=[1+(y-1)x] $ $ y= $ number of ions $ x= $ degree of ionisation $ i=3 $ for $ BaC{{l}_{2}}x=1 $ (strong electrolyte) $ i=2 $ for $ KCl\text{ }x=1 $ (strong electrolyte) $ i=(1+x) $ for $ C{{H}_{3}}COOH\text{ }x<<1 $ (weak) $ i=1 $ for sucrose (non-electrolyte) $ i $ (for $ BaC{{l}_{2}} $ ) $ >KCl>C{{H}_{3}}COOH>sucrose $ Thus, is also true. (d) $ \Delta {{T}_{f}}={{K}_{f}}m. $ $ {{K}_{f}} $ is dependent on solvent. Thus, freezing points [ $ =T $ (solvent) $ -\Delta {{T}_{f}} $ ) are different. Thus, (d) is false.