Chapter 8 · Chemistry
Aldehydes, Ketones and Carboxylic Acids: The Whole Chapter in One Minute
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The chapter in one place: the polar, planar C=O group; how aldehydes and ketones are made; nucleophilic addition; aldol and Cannizzaro; Tollens' and Fehling's tests; and why carboxylic acids are acidic.
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Key points
- The carbonyl carbon is sp², planar; C=O is polar (O δ⁻, C δ⁺), so nucleophiles attack the carbon.
- Made by oxidation of alcohols, ozonolysis of alkenes, hydration of alkynes, Rosenmund reduction of acyl chlorides.
- Nucleophilic addition: HCN → cyanohydrin, alcohols → acetal, NH₂–Z → oxime, hydrazone; α-H → aldol, no α-H → Cannizzaro.
- Tollens' silver mirror and Fehling's red precipitate for aldehydes; carboxylate resonance makes RCOOH acidic, EWGs raise acidity.
The chapter on one page
| Idea | What to remember |
|---|---|
| Structure | sp², planar, polar C=O |
| Preparation | [O] of alcohols, ozonolysis, alkyne hydration, Rosenmund |
| Typical reaction | nucleophilic addition |
| α-H? | yes: aldol; no: Cannizzaro |
| Tests | Tollens' (silver mirror), Fehling's (red ppt): aldehydes |
| Acids | carboxylate resonance → acidity; EWG ↑ acidity |
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