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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: ponyoponyo on April 01, 2013, 09:26:51 AM

Title: Distillation Curve (Vapor Line & Liquid Line)
Post by: ponyoponyo on April 01, 2013, 09:26:51 AM

I need to know if my answer to this question is correct

What would be the comp of the first liquid to occur if a gas mixture containing 50% B were cooled from 100^oC?

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fi48.tinypic.com%2F2z9bbi9.jpg&hash=4a56ef10ce039e2c20d7af80b51ed7df01fdb2d1)

I know the top line is the vapor line, the composition of the vapor which shows how much enrichment in the lower boiling component occurs. And I know the bottom line is the liquid line, the boiling point of the mixture.  think the answer would be 28% B. To do this I started at 50% B at the top of the graph, went straight down to the liquid line, went left to the vapor line, and then straight down the the B % composition and got 28% B. Is my thinking correct?

Title: Re: Distillation Curve (Vapor Line & Liquid Line)
Post by: curiouscat on April 01, 2013, 09:53:27 AM

Think you are wrong. It will be ~70%.

As a cross check, Is A more volatile or B here?  Is the more volatile component concentrated in liq. or vap. phase?