Question 13

[kbshah6109]

The second cylinder was above the boiling point of ethyl acetate, so all of the ethyl acetate in liquid form should not be present, so then it should contain pure butanol as should cylinder 3 and the flask.

can't choice C and D both be the answer.

[admin]

If water is boiled at 105 degrees celsius, will any water evaporate? Certainly. What you did was to assume that all the ethyl acetate was boiled off after GC-1 was collected (which can't be assumed because no temperature was given). In fact, as in the example of water, we must assume that there was some ethyl acetate and that some of it is being boiled off.

On the other hand, it is quite clear from the experiment that the RB must contain a particularly pure form of butanol since everything has been done to boil off ethyl acetate.

[shawrk]

Could you please explain how the RB flask would have the purest concentration of butanol when it is in a 1:1 solution with the ethyl acetate. I think I am missing something simple in the interpretation.

[admin]

The 1:1 concentration is before the experiment started (30 mL). The question refers to "upon completion of the experiment" which is when there is only 8 mL left in RB and because it is way above the boiling point of ethyl acetate, there must only be a rather pure form of butanol which, if the experiment continued at the last stated temperature, would indeed be boiled off.

[admin]

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