1) You have a two component mixture (A and B) containing 50% molar of each compo

Question

1) You have a two component mixture (A and B) containing 50% molar of each component. This mixture has an azeotrope distillate composition 95% A and 5% B. Describe what you would observe when carrying out a distillation.

2) You have a compound that boils at 300oC at 1 atm pressure but decomposes above 100oC. What pressure is the maxium at which you could successfully distill this material?

3) You distill a material, boiling point 200oc at 1 atm, at 40 mm pressure. What boiling point would you expect?

Explanation / Answer

1) As we see that Composition A has azeotrope distillation compositon of 95% and the concentration of A present is 0.2M. When we distill it a particular temperature, we will get a Vapour with different compostion C1. And when we distill it again, it will produce another composition C2 with different Vapour. If we continue doing this again and again, we will end up with a vapour of composition of 95% A and when we condense we get 95% A. So, it is impossible to get pure A or B by just distilling if the mixture contains less than he azeotrope compostion.

2)  There is a rule that when we half the pressure, the boiling boing point decreases by 10 C.
As we see that the actual boiling point is 300 C at 1 atm, we need to decrease the pressure such that the temperature is lowered to 100 C.
The temperature is lowered by 300-100 = 200 C, which means the temperature will be lowered by 10 C for 20 number of times. So the pressure needs to be lowered to 1*(1/2)^20 atm.

3) For this queston also same concept can be applied. We increase the pressure here, so we have to increase temperature also.
1 atm, 200 C
2 atm, 210 C
4 atm, 220 C
8 atm, 230 C
16 atm, 240 C and so on , we can get a temperature near around not exact though.

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.