Describe the differences between aldehydes and ketones.

Aldehydes and ketones are both organic compounds containing a carbonyl group, but they differ in their structure and properties.

Aldehydes have a carbonyl group (-C=O) at the end of a carbon chain, while ketones have a carbonyl group between two carbon atoms. This structural difference affects their physical and chemical properties. Aldehydes have a lower boiling point than ketones because they can form hydrogen bonds with water molecules due to the presence of a terminal -OH group. Ketones, on the other hand, have a higher boiling point because they cannot form hydrogen bonds with water.

Aldehydes are more reactive than ketones because they have a more polar carbonyl group and a hydrogen atom attached to the carbonyl carbon. This makes them more susceptible to nucleophilic attack and oxidation. Aldehydes can be easily oxidized to form carboxylic acids, while ketones are resistant to oxidation.

Aldehydes and ketones also differ in their chemical reactions. Aldehydes can undergo nucleophilic addition reactions with compounds such as hydrogen cyanide and sodium bisulfite, while ketones cannot. Ketones, however, can undergo nucleophilic addition reactions with compounds such as Grignard reagents and organolithium compounds, which are not possible with aldehydes.

In summary, aldehydes and ketones are similar in that they both contain a carbonyl group, but differ in their structure, physical and chemical properties, and reactivity towards different compounds.