Practical Techniques In Organic Chemistry

Question 1

What is the best way to determine which layer is organic?

Answer 1

• add water to your reaction mixture
• the aqueous layer gets bigger

Question 2

How is the organic layer separated?

Answer 2

Using a separating funnel:
1. Ensure the tap is closed and place the mixture into the funnel
2. Invert the funnel and allow the layers to settle
3. Place a flask under the tao and open until the whole bottom layer has left and repeat into a different flask for the second layer and label the flasks accordingly

Question 3

How are acid impurities removed from a reaction mixture?

Answer 3

1. Adding aqueous sodium carbonate and shaking the mixture in a separating funnel
2. Slowly open the tap whilst holding the funnel upside down to allow the CO2 to escape

Question 4

What are some common drying agents?

Answer 4

1. Anhydrous calcium chloride (used for hydrocarbons)
2. Anhydrous calcium sulphate
3. Anhydrous magnesium sulphate

Question 5

Describe the procedure to drying an organic liquid.

Answer 5

Using a spatula add some of the drying agent to the organic liquid in a conical flask and mix and leave to dry

Question 6

Why is redistialltion used?

Answer 6

• if boiling pints are relatively close together then the liquid is redistilled and only collected at a specific temperature