Chapter 16 - Organic Synthesis

Question 1

What is reflux?

Answer 1

Heating under reflux is vaporisation followed by condensation back to the original container.
- Using reflux reactants can be heated without the products escaping by boiling of reactants (prevents gas escaping).

Question 2

What is distillation?

Answer 2

Vaporisation followed by condensation to a different container.

• It is used to separate a liquid or a mixture of liquids from a solution.
• Different liquid components can be separated by collection at different boiling points.

Question 3

If an organic liquid and water are immiscible, how can the two liquids be separated?

Answer 3

If an organic liquid and water are immiscible, the organic liquid and water form separate layers. The two layers are separated by adding the mixture to a separating funnel and running off each layer into different containers.

Question 4

How can you remove acid impurities from a mixture?

Answer 4

Acid impurities can be removed by adding a solution of Na2CO3 and shaking the mixture.

Any acid impurites react with Na2CO3 forming a separate layer to the organic liquid which can be removed using a separating funnel.

Question 5

How can you remove any water impurities left from a mixture after using a separating funnel?

Answer 5

A drying agent (e.g. anhydrous salt) can be used to remove water from a mixture. The anhydrous salt takes in the water forming the hydrated salt. The organic liquid can be decanted from the solid hydrated salt.