Structures of alcohols, carboxylic acids and esters

Question 1

How is ethanol made?

Answer 1

Ethanol can be made from ethene gas. Ethene is the main by-product produced in cracking. Ethene gas can react with steam to make ethanol.

Question 2

Simplified explanation of alcohol structure:

Answer 2

imagine removing an H atom from an alkane molecule and replacing it with an -OH group. This would give alcohol.

Question 3

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

Answer 3

methanol

ethanol

propanol

butanol

Question 4

The general formula for alcohol’s is…

Answer 4

Cn,H2n+1,OH

or since the H from OH is counted, the same as alkenes + O

Cn,H2n+2,O

Question 5

Reactions of alcohols: combustion

Answer 5

The alcohols undergo
complete combustion
to form carbon dioxide and water. For example, ethanol is used as a fuel:

ethanol + oxygen → carbon dioxide + water

IF less oxygen is present,
incomplete combustion
will occur, producing water and either carbon monoxide or carbon.

Question 6

Reactions of alcohols: reaction with sodium

Answer 6

If a small piece of sodium is dropped into ethanol, bubbles of hydrogen gas are produced and the liquid contains sodium ethoxide. The reaction is:

sodium + ethanol → sodium ethoxide + hydrogen

Question 7

Reactions of alcohols: oxidation

Answer 7

The alcohols can also be oxidised without combustion
to produce carboxylic acids.
This is done with an oxidising agent.

ethanol + oxidising agent → ethanoic acid + water

The same reaction takes place if ethanol is left exposed to air. Microbes in the air produce ethanoic acid from the ethanol.

Question 8

What is ethanoic acid?

Answer 8

vinegar