Alcohols

Question 1

What functional group do alcohols contain?

Answer 1

• OH

Question 2

How can ethanol be oxidized?

Answer 2

Ethanol can be oxidized by:

• burning in air or oxygen
• reacting with oxygen in the air to form ethanoic acid
• heating with potassium dichromate(VI) in dilute sulfuric acid to form ethanoic acid.

Question 3

How is ethanol manufactured?

Answer 3

• By reacting ethene with steam in the presence of a phosphoric acid catalyst at a temperature of about 300(degrees Celsius) and a pressure of about 60-70atm,

OR

• By the fermentation of glucose in the absence of air at an optimum temperature of about 30(degrees Celsius) using the enzymes in yeast.

Question 4

Why is fermentation carried out at a low temperature?

Answer 4

• To prevent the enzymes in yeast from denaturing.
• If the temperatures are too high the enzymes denature.
• If the temperatures are too low, the enzymes would be inactive making the process slow.

Question 5

What happens if fermentation occurs in the air?

Answer 5

• Enzymes in the yeast produce carbon dioxide and water instead of ethanol.
• Ethanol oxidizes to ethanoic acid.