ppractical 5- distillation

Question 1

what are features of the condenser

Answer 1

open at both ends
cold water flows around the outside

Question 2

purpose of condenser

Answer 2

cools hot vapour and condenses it into liquid

Question 3

why add anti-bumping granules

Answer 3

prevent the formation of large bubbles

Question 4

why is reflux used to oxidise a primary alcohol to a carboxylic

Answer 4

reflux doesn’t allow any reactant vapors to escape

Question 5

draw a reflux apparatus

Answer 5

refer to photo on phone

Question 6

Describe what happens when a reaction mixture is refluxed and why it is necessary, for complete oxidation to a carboxylic acid

Answer 6

Ethanol and acidified potassium dichromate(VI) are heated to boiling point for a prolonged time

· Ethanal vapour is formed which escapes from the liquid mixture and is then condensed back into liquid and returned to the reaction mixture

· Any ethanal and ethanol that initially evaporates can then be oxidised

Question 7

draw a distillation appartus

Answer 7

refer to photo on phone

Question 8

What happens to the aldehyde as it is produced during distillation?

Answer 8

· Distillation allows the aldehyde to escape the reaction mixture and prevents further oxidation

Question 9

Ethanol can be oxidised to ethanal or ethanoic acid. Describe how ethanal can be made in high yield, as opposed to ethanoic acid.

Answer 9

· Use distillation

· Heat at the boiling point of ethanal

· Collect ethanal as it is distilled off