Mole fraction of Heptane =10025+1143525/100=0.5570.25=0.45 XHep tane =0.45. ∴ Mole fraction of octane =0.55=Xoctane Total pressure =∑XiPi0 =(105×0.45)+(45×0.55)kPa =72.0KPa
JEE Main 2010 — Chemistry Physical Chemistry
On mixing, heptane and octane form an ideal solution. At 373 K, the vapour pressures of the two liquid components (heptane and octane) are 105kPa and 45kPa respectively. Vapour pressure of the solution obtained by mixing 25.0 g of heptane and 35 g of octane will be (molar mass of heptane =100 g mol−1 an dof octane =114 g mol−1 ).
Held on 30 Apr 2010 · Verified 6 Jul 2026.
72.0kPa
36.1kPa
96.2kPa
144.5kPa
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