Molar mass of CH2Cl2=12×1+1×2+35.5×2=85 g mol−1 Molar mass of CHCl3=12×1+1×1+35.5×3=119.5 g mol−1 Moles of CH2Cl2=40 g/85 g mol−1=0.47 mol Moles of CHCl3=25.5 g/119.5 g mol−1=0.213 mol Total number of moles =0.47+0.213=0.683 mol Mole fraction of component 2 =0.47 mol/0.683 mol=0.688 Mole fraction of component 1 =1.00−0.688=0.312 We know that: PT=p10+(p20−p10)x2=200+(415−200)×0.688=200+147.9=347.9 mmHg
Vapour pressure of chloroform ( CHCl_3 ) and dichloromethane ( CH_2 Cl_2 ) at 25° C are 200 ~mm Hg and 415 ~mm Hg respectively. Vapour pressure of…
NEET UG 2012 — Chemistry Physical Chemistry
2012mcqeasy
Vapour pressure of chloroform (CHCl3) and dichloromethane (CH2Cl2) at 25∘C are 200 mmHg and 415 mmHg respectively. Vapour pressure of the solution obtained by mixing 25.5 g of CHCl3 and 4Og of CH2Cl2 at the same temperature will be: [Molecular mass of CHCl3=119.5 g/mol and molecular mass of CH2Cl2=85 g/mol ]
Official previous-year question
Held on 30 Apr 2012 · Verified 9 Jul 2026.
Options
- A
173.9mmHg
- B
615.0mmHg
- C
347.9mmHg
- D
28.5mmHg
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