Agas stream contains 18.0 mol% hexane and the remainder nitrogen. the stream flows to a condenser, where its temperature is reduced and some of the hexane is liquefied. the hexane mole fraction in the gas stream leaving the condenser is 0.0500. liquid hexane condensate is recovered at a rate of 1.50 l/min

There is no question specified for this problem. Based on my understanding, there are 5 possible questions that would come up. Once you know them, the whole problem is solved. They are:

a.) The amount of entering gas stream (denoted as A)
b.) The amount of exiting gas stream (denoted as B)
c.) The amount of condensate (denoted as C)
d.) Mole fraction of liquid hexane (x,h)
e.) Mole fraction of liquid nitrogen (x,n)

In order to solve this, we apply mass balance.
Overall Mass Balance: A = B + C
Hexane Balance: 0.18A = 0.05B + 1.5
Nitrogen Balance: 0.82A = 0.95B + (C - 1.50)

Solving the equations simultaneously:
0.18(B+C) = 0.05B + 1.50
C = (1.5 - 0.13B)/0.18

0.82[B + ((1.5 - 0.13B)/0.18)] = 0.95 + ((1.5 - 0.13B)/0.18) - 1.5
Solving for B,
B = 1 L/min
Then,
C = (1.5 - 0.13(1))/0.18 = 7.611 L/min
A = 1 L/min + 7.611 L/min = 8.611 L/min
x,h = 1.5/C = 1.5/7.611 = 0.197
x,n = 1 - 0.197 = 0.803

As a summary, the possible answers to the possible questions are:
a.) 8.611 L/min entering gas stream
b.) 1 L/min exiting gas stream
c.) 7.611 L/min condensate
d.) The condensate is 19.7 mol% hexane
e.) The condensate is 80.3 mol% nitrogen