Question
Calculate the mole fraction of solute in solution if vapour pressure of a solution and pure solvent are 27 mm Hg and 30 mm Hg respectively at 298 K.
MHT CET
Chemistry
Solutions
2026
MHT CET 2026 (18 April Shift 2)
MHT CET Chemistry Question (2026) — Solution
Options
- A. 0.9
- B. 0.1
- C. 0.4
- D. 0.6
Answer
B. 0.1
Step-by-step solution
According to Raoult's law, the relative lowering of vapour pressure is equal to the mole fraction of the solute. P^0 - P_s P^0 = x_ solute Given P^0 = 30 mm Hg and P_s = 27 mm Hg . x_ solute = 30 - 27 30 x_ solute = 3 30 = 0.1 Answer: 0.1
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