Paper 2 - Alcohols

Question 1

What functional group do alcohols contain?

Answer 1

-OH

Question 2

How can ethanol be oxidised?

Answer 2

• burning in air or oxygen (complete combustion)
• reaction with oxygen in the air to form ethanoic acid (microbial oxidation)
• heating with potassium dichromate(VI) in dilute sulfuric acid to form ethanoic acid

Question 3

How can ethanol be manufactured?

Answer 3

• reacting ethene with steam in the presence of a phosphoric acid catalyst
  at a temperature of about 300 ºC and a pressure of about 60–70 atm
• the fermentation of glucose, in the absence of air, at an optimum temperature of about 30 ºC and using the enzymes in yeast

Question 4

What are the reasons for fermentation in the absence of air?

Answer 4

Oxygen converts the ethanol to ethanoic acid which is undesired

Question 5

What are the reasons for fermentation at optimum temperature?

Answer 5

• Fermentation must occur at 30℃
• At lower temperatures, the rate of reaction slows down
• At higher temperatures, they active site of the enzyme in the yeast will denature and the reaction would stop