Consider a water/ethanol Starting with a mole fraction of X 1 =0.12 for ethanol,
ID: 504229 • Letter: C
Question
Consider a water/ethanol
Starting with a mole fraction of X1=0.12 for ethanol, the liquid is heated slowly from 350K to 370K. 4What are the mole fraction of ethanol and water-
a)In the vapor phase, at the boiling point (give the boiling point)?
B)In the liquid phase, when the last of the liquid disappears (give the temperature)?
C)What happens for the same heating process if the starting point of X1=0.9 for ethanol?
Vapor-Liquid Equilibrium Mixture of Ethanol and Water 374 P-101.325 kPa 372 370 368 366 Vapor Composition 364 362 360 358 Azeotropic 356 Point 354 Liquid Composition 352 350 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Mole Fraction of Ethanol [molmoll Pure Pure Water EthanolExplanation / Answer
1) At x1= 0.12, mole fraction of ethanol = 0.12 and mole fraction of water = 1-0.12 = 0.88
2) At X1= 0.12, the boiling point lies on the vapour line which meets X1= 0.12 at approximately temperature of 370K. So, boiling point of X1=0.12 ethanol is 370K
3) At X1=0.12, the point where last liquid disappears if where the point is on liquid line. So, at X1=0.12, going up on heating, the meeting point on the liquid line is at somewhere around 358K.
4) For X1= 0.9, now the mixture is a azeotrope, means it behaves as a single component. Thus mole fraction of ethanol = 0.9 and water = 0.1. And boling point = temperature of liquid disappreance = approx. 351.5K.
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