Assignment 8
Q.1. At 360 K the vapour pressures of n-heptane and toluene are respectively 71.2 kPa and 48.9
kPa. Determine the composition of the liquid and vapour in equilibrium at 360 K and 65 kPa, if it
is given that n-heptane and toluene form ideal solutions.
Q.2. The vapour pressures of two pure liquids A and B are respectively 100 kPa and 60 kPa at
320 K. The concentration of A in the vapour in equilibrium with a solution of A and B is found
to be 50% (mol). Determine the following:
(a) The composition of the liquid
(b) The total pressure of the vapour.
Q.3. A liquid mixture containing 65 mol % benzene and 35 mol % toluene is subjected to flash
vaporization at 363 K and 101.3 kPa. The vapour pressure of benzene at this temperature is
136.09 kPa and the vapour pressure of toluene is 54.21 kPa. Flash vaporization is essentially an
equilibrium stage operation. Calculate the mole percent of the feed that is vaporized.