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Distillation.pdf - Microsoft Edge online.ksu.edu/COMS/player/content/_16794/content/Modules/Distillation.pdf 5of 8 160 140 Temp (C) 120 100 80 60 methanol 10 80 60 20 80 60 100 Figure 5-2. Phase diagram for methanol-propionic acid Each of these vaporization-condensation steps represents a theoretical plate Starting with the 80:20 mixture, we would need approximately 4 theoretical plates to effectively separate this mixture. As we distill the mixture the liquid becomes richer in propionic acid and as this happens we need more theoretical plates to separate the mixture. Table 4-1 shows the approximate number of theoretical plates required to separate mixtures based on the differences in their boiling points. Notice that as the boiling point difference between the two components decreases, the number of theoretical plates required to separate the mixture increases. When the boiling point difference is large, fewer theoretical plates are t O Ask me anything 2:14 PM 12/20/2015Explanation / Answer
In your book , below the text of this question you have a phase diagram. Use it.I have the complete text of this question. You have here the complete answer.
40 mL x 0.89 g/mL / 102.1 g/mol = 0.35 mol MB
10 mL x 0.96 g/mL / 88.1 g/mol = 0.11 mol BA
Total moles ……………………..0.46 mol
MB mol % = 100 x 0.35/0.46 = 76%
BA mol % = 100 x 0.11/0.46 = 0.24%
(in the image draw a first vertical line at MB = 76%.
1.The boiling point is the temperature of the first horizontal line, my estimation is about 103..104ºC.
2. draw the horizontal line. Look at the left end of the first horizontal line, draw a vertical line and read the composition on the abscissa : 95% MB and 5% BA. These values are the vapour composition and the composition of the distillate for a simple distillation (same values).
3. Each horizontal line is a vaporization. Each vertical line is a condensation. Each pair vaporization-condensation is a theoretical plate. For three theoretical plates, the distillate (first fraction) is very close to pure MB (>99%).
Note. Observe that after the collection of the first fraction, you have to rise the temperature to 160 ºC to start a vaporization of the remaining pure BA. Observe that two theoretical plates are quite enough (see also Table 4.1, the boiling point difference is 60ºC)