Distillation: fractional distillation | Exit Quiz | Oak National Academy

What are miscible fluids?

• liquid and solid substances that can mix

• liquids and/or gases which can dissolve in each other

• any liquids that are mixed together

Answer explanation

Miscible fluids are liquids and/or gases which can dissolve in each other.

___ are produced by fractional distillation. They may be pure, i.e. contain one component, or a mixture containing multiple components with similar boiling points.

Answer explanation

Fractions are produced by fractional distillation. They may be pure, i.e. contain one component, or a mixture containing multiple components with similar boiling points.

What is the purpose of fractional distillation?

• to mix multiple fluids together with different boiling points

• to separate multiple fluids with different boiling points

• to produce a single fraction

• to produce a single pure fluid

Answer explanation

Fractional distillation is used to separate fluids with different boiling points.

Match the following statements to make complete sentences related to distillation:

• Fractions are ...

• to create a temperature gradient to separate fluids into fractions.

• A fractionating column can be used ...

• pure substances, or mixtures with similar boiling points.

• Fractional distillation can be used ...

• to separate multiple miscible fluids with a range of boiling points.

• Simple distillation can be used to ...

• separate two miscible liquids with very different boiling points.

Answer explanation

Simple distillation separates two miscible liquids with very different boiling points while fractional distillation separates multiple miscible fluids with a range of boiling points using a fractionating column to produce pure fractions or mixtures.

A mixture of liquid fractions; X (b.p. 40 - 100°C), Y (b.p. 120 - 160°C) and Z (b.p. 180 - 200°C) was heated quickly to 150°C. What would be found in the distillate?

• X, Y and Z

• X only

• X and Y

• Y

Answer explanation

X and Y as they contained substances that would boil at 150°C (all of X and those in Y with bpts ≤ 150°C). All the substances in Z had boiling points above 150°C and so would not have boiled.