Question

Benzene and toluene form an ideal solution over the entire range of composition. Hie vapour pressure of pure benzene and toluene at $T (K)$ are $50\, mm \,Hg$ and $40\, mm \,Hg$ respectively. What is the mole fraction of toluene in vapour phase when $117\, g$ of benzene is mixed with $46\, g$ of toluene ? (molar mass of benzene and toluene are $78$ and $92\, g\, mol^{-1}$ respectively)

• A. 0.78
• B. 0.21
• C. 0.64
• D. 0.35

Answer 1

Answer: (B)

0.21

Answer 2

Answer (b) 0.21