Question

Why carboxylic acids act neither like aldehydes nor like ketones based on resonance?

Answer 1

Because they are different molecules?

Explanation:

Just to retire this question, we got carboxylic acids...`RCO_2H`..versus aldehydes, `RC(=O)H`, versus ketones, `RC(=O)R` versus alcohols, `RCH_2OH` versus alkanes, `RCH_3`...and the oxidation numbers of the ipso carbon are....

`CO_2` `,C(+IV)`

`RCO_2H` `,C(+III)`

`RC(=O)R` `,C(+II)`

`RC(=O)H` `,C(+I)`

`RCH_2OH` `,C(-I)`

`RCH_2R` `,C(-II)`

`RCH_3` `,C(-III)`

`CH_4` `,C(-IV)`

Often we speak of the oxidation of carbon in organic chemistry..