Question

Consider a system for heating a liquid benzene/toluene solution to distill a pure benzene vapor. A particular batch distillation unit is charged initially with 100 mol of a 60 percent mol benzene/40 percent mol toluene mixture. Let L (mol) be the amount of liquid remaining in the still, and let x (mol B/mol) be the benzene mole fraction in the remaining liquid. Conservation of mass for benzene and toluene can be applied to derive the following relation [Felder, 1986).

L=100(x/0.6)⁰. ⁶²⁵(1-x/0.4)⁻¹. ⁶²⁵
Determine what mole fraction of benzene remains when L 70. Note that it is difficult to solve this equation directly for x. Use a plot of x versus L to solve the problem

Answer 1

To determine the mole fraction of benzene remaining, we can use the given relationship between L and x and plot x versus L.

Step-by-step explanation:

In order to determine the mole fraction of benzene remaining when L = 70, we can use the given relationship between L and x, which is L = 100(x/0.6)0.625(1-x/0.4)-1.625. However, solving this equation directly for x is difficult, so we can use a plot of x versus L to solve the problem.