A-Level Chemistry: Alcohols Syllabus

The alcohols topic in A-level Chemistry focuses on the structure, properties, preparation, and reactions of alcohols. It is an important part of organic chemistry and links closely with alkenes, halogenoalkanes, aldehydes, ketones, carboxylic acids, and esters.

1. What Alcohols Are

• Alcohols contain the hydroxyl functional group, -OH.
• Students should recognise alcohols from their displayed, structural, and skeletal formulae.
• Alcohols are classified as primary, secondary, or tertiary.

2. Physical Properties

• Alcohols are polar because of the O-H bond.
• They can form hydrogen bonds.
• This explains why simple alcohols are often soluble in water.
• It also explains why alcohols have higher boiling points than similar alkanes.

3. Preparation of Alcohols

• Alcohols can be made by the hydration of alkenes using steam and an acid catalyst.
• Ethanol can also be produced by fermentation of glucose.
• Students may need to know the conditions, advantages, and disadvantages of these methods.

4. Reactions of Alcohols

• Combustion: alcohols burn in oxygen to release energy.
• Oxidation:
  • Primary alcohols can be oxidised to aldehydes and then to carboxylic acids.
  • Secondary alcohols can be oxidised to ketones.
  • Tertiary alcohols are not easily oxidised.
• Elimination (dehydration): alcohols can lose water to form alkenes.
• Some specifications also include conversion of alcohols into haloalkanes.

5. Reagents, Conditions, and Tests

• A common oxidising agent is acidified potassium dichromate(VI).
• Students should know how reaction conditions affect the oxidation product formed.
• You may also need to know tests used to distinguish aldehydes from ketones.

6. Related Organic Chemistry Links

• Alcohols link to alkenes through hydration and dehydration reactions.
• They link to aldehydes, ketones, and carboxylic acids through oxidation.
• They also link to esters through esterification reactions.

7. Practical and Applied Ideas

• Students may carry out the oxidation of ethanol as a practical activity.
• The topic may include discussion of biofuels, especially ethanol.
• Environmental and economic issues surrounding alcohol fuels may also be considered.