Interpretation:
The reason for the observed boiling point for the first drop of the collected distillate of pentane and hexane to be higher than the boiling point of pentane should be determined.
Concept introduction:
Distillation is a liquid-gas separation technique for two or more liquids on the basis of their difference in boiling point or vapor pressure.
Vapor pressure is pressure exerted by vapor phase of liquid produced due to an increase in the molecular kinetic energy of the liquid phase or due to the increase in temperature.
The temperature at which atmospheric pressure exerted on liquid equals to its vapor pressure is known to be its boiling point. Vapor pressure of the component decide boiling point of any mixture. Impurities in the mixture might result in an increase or decrease of observed boiling point.
Explanation of Solution
Hexane and pentane are mutually soluble in each other and their solution boil at a temperature intermediate of their boiling point.
In case of pentane and hexane that have
The first drop of the distillate obtained will have a higher boiling point than the pentane as hexane that is present in the mixture will act as impurity and will lead to an increase in its observed boiling point.
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Chapter 12 Solutions
Laboratory Techniques in Organic Chemistry
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