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A mixture holds butan-1-ol (boiling point 118 °C), 2-methylpropan-1-ol (108 °C) and…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A mixture holds butan-1-ol (boiling point ), 2-methylpropan-1-ol () and 2-methylpropan-2-ol (). It is separated by fractional distillation. Find the temperature gap between the lowest and the highest boiling liquid, and the smallest gap between two neighbouring liquids. Say which liquid distils first.
Need a reminder? The key ideaShow
Hydrogen bonding raises the boiling point. Branching lowers it among isomers. Mass of a component volume density. Mole fraction of A . Energy to vaporise .
The worked solution
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Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. Boiling points , and .
Step 1. Total gap. .
Step 2. Neighbouring gaps. and . The smallest is .
Step 3. Order. 2-Methylpropan-2-ol distils first, then 2-methylpropan-1-ol, then butan-1-ol.
Check. The more branched the isomer, the lower the boiling point, so the order follows the shape. The gap is the hardest to separate, and needs a longer fractionating column.
Answer: and .
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