Question

Application: Fractional distillation is the most common separation and purification technique used in the refinement of crude oil. Propose an experimental design using distillation that will allow a scientist to isolate a mixture containing octane (b.p. 120), kerosene (b.p. 200) and asphalt (b.p. 525).

Answer 1

An experimental design for separating octane, kerosene, and asphalt using fractional distillation involves heating the mixture to successively higher temperatures to isolate each substance based on its unique boiling point, while using a fractionating column for efficient separation.

Step-by-step explanation:

To design an experimental procedure to isolate a mixture containing octane (b.p. 120), kerosene (b.p. 200), and asphalt (b.p. 525) through fractional distillation, the following steps should be taken:

• Heat the mixture in a distillation flask until it reaches the boiling point of the lowest boiling component—octane. As octane vaporizes, it will ascend the fractionating column.
• As the vapor cools, octane will condense at a point in the column that corresponds with its lower boiling point and can be collected.
• Increase the temperature to reach the boiling point of kerosene. Kerosene will follow similarly, condensing at a higher point in the column than octane due to its higher boiling point, and will be collected.
• Maintain the temperature below the boiling point of asphalt to avoid its distillation, since it has a much higher boiling point. This will leave asphalt at the bottom of the distillation flask as residue.

This method takes advantage of the differing boiling points of the substances, allowing the scientist to separate and collect them individually. The precise control of temperature and the use of a properly designed fractionating column are crucial to the successful separation and purification of these components.