A student is investigating the boiling points of straight-chain carboxylic acids. The table below shows the boiling points of some carboxylic acids:
| Name of carboxylic acid | Number of carbon atoms | Boiling point (∘C\phantom{}^{\circ}\text{C}∘C) |
|---|---|---|
| Methanoic acid | 1 | 101 |
| Ethanoic acid | 2 | 118 |
| Propanoic acid | 3 | 141 |
| Pentanoic acid | 5 | 186 |
| Hexanoic acid | 6 | 205 |
Estimate the boiling point of butanoic acid (which contains 4 carbon atoms) by considering the trend in the data.
Draw the displayed formula of butanoic acid, C3H7COOH\text{C}_3\text{H}_7\text{COOH}C3H7COOH.
Carboxylic acids react in a similar way because they contain the same functional group. Identify this functional group.
Ethanol (C2H5OH\text{C}_2\text{H}_5\text{OH}C2H5OH) is oxidised to ethanoic acid (CH3COOH\text{CH}_3\text{COOH}CH3COOH). State the formula of the alcohol that is oxidised to propanoic acid (C2H5COOH\text{C}_2\text{H}_5\text{COOH}C2H5COOH).