MHT CET202525 Apr 2025Evening ShiftChemistrySolutionsActual
Calculate the vapour pressure of solution if relative lowering of vapour pressure and vapour pressure of pure solvent are 0.018 and 18 mm Hg respectively at 300 K .
Options
- A18.32 mm Hg
- B17.08 mm Hg
- C17.68 mm Hg
- D18.60 mm Hg
Correct answer
C. 17.68 mm Hg
Step-by-step solution
Vapor pressure lowering is a colligative property described by Raoult's law for non-volatile solutes: P^0 - P_s P^0 = relative lowering Given a relative lowering of 0.018 and a pure solvent vapor pressure P^0 = 18 mm Hg , substitute into the equation: 18 - P_s 18 = 0.018 Solving for P_s : 18 - P_s = 0.018 18 18 - P_s = 0.324 P_s = 18 - 0.324 = 17.676 mm Hg Rounded to two decimal places, P_s = 17.68 mm Hg , which corresponds to option C . Final answer: C