4.7.2.3 Alcohols

Question 1

What functional group do alcohols contain?

Answer 1

• OH

Question 2

What are the first four members of the homogeneous series of alcohols?

Answer 2

• Methanol
• Ethanol
• Propanol
• Butanol

Question 3

How can alcohols be represented?

Answer 3

• CH3CH2OH
  or
  H H
  H - C - C - O - H
  H H

Question 4

Describe what happens when alcohols react with sodium.

Answer 4

• When alcohols react with sodium, a salt will be formed plus hydrogen
• The salt formed from the reaction with sodium and ethanol is called sodium ethoxide

Question 5

Describe what happens when alcohols burn in air.

Answer 5

• Due to their formability they undergo complete combustion in air
• Alcohol + O2 = CO2 + H2O

Question 6

Describe what happens when alcohols react with water.

Answer 6

• They can dissolve in water to form a solution
• Are not acidic and therefore have a neutral pH

Question 7

Describe what happens when alcohols react with an oxidising agent.

Answer 7

• It will oxidise and from a carboxylic acid

Question 8

What are the main uses of the alcohols?

Answer 8

• We can use alcohols as fuels (burning and alcohol to release energy)
• As solvents in industry (Alcohols are often used instead of water as they can dissolve things that water can not (typically things like hydrocarbons, lipids, fats and oils))

Question 9

When are aqueous solutions of ethanol produced?

Answer 9

• When sugar solutions are fermented using yeast

Question 10

What are the conditions used for fermentation of sugar using yeast?

Answer 10

• Sugars dissolved in water
• Mixed with yeast
• Anaerobic conditions (no air can get in)
• 25°C – 35°C temperature

Question 11

What is the general formula?

Answer 11

• CnH2n+1OH

Question 12

What are the properties of alcohol?

Answer 12

• Flammable
• Soluble
• Can be oxidised (to make carboxylic acids)