A phase diagram of temperature versus composition for a mixture of the two volatile liquids octane (bp = and decane (bp = 126°C)is shown.
-Assume that the vapor at point c is condensed and reboiled.What is the liquid composition of the condensed vapor prior to reboiling?
A)100% decane
B)composition at point b
C)composition at point d
D)composition at point e

Question

A phase diagram of temperature versus composition for a mixture of the two volatile liquids octane (bp =  and decane (bp = 126°C)is shown. 
-Assume that the vapor at point c is condensed and reboiled.What is the liquid composition of the condensed vapor prior to reboiling?
A)100% decane 
B)composition at point b 
C)composition at point d 
D)composition at point e

Quizplus · Accepted Answer

At point c, the vapor in equilibrium with the liquid has a composition that lies on the line separating the two liquid phases. When this vapor is condensed and reboiled, its composition will lie on the line separating the two liquid phases in the reboiler. This line passes through point d, so the liquid composition of the condensed vapor prior to reboiling is the composition at point d, which is approximately 76% decane and 24% octane.

A Phase Diagram of Temperature Versus Composition for a Mixture