Question

How do aldehydes and ketones differ from alcohol?

Answer 1

An alternative means of differentiation is to consider the degree of oxidation of the ipso carbon.

Explanation:

Aldehydes and ketones are the oxidation products of alcohols, and we could assign formal oxdation states.

The oxidation state of the ipso carbon in `H_3C-CH_2OH` is `-I`; in `H_3C-C(=O)H`, `+I`, and in `H_3C-C(=O)OH`, `+III`. Of course `+III` represents its maximum oxidation state (`CO_2` can be formed, but here the chain is broken).

By comparison, we could assign the formal oxidation numbers of carbon in say propane or butane: `H_3stackrel(""^(-)III)C-stackrel(""^(-)II)CH_2CH_3`, or `H_3stackrel(""^(-)III)C-stackrel(""^(-)II)CH_2stackrel(""^(-)II)CH_2CH_3`

Certainly we use oxidizing agents to synthesize ketones and aldehydes from alcohols.