Aldehydes, Ketones and Carboxylic Acids
Carbonyl compounds contain C=O; aldehydes and ketones undergo nucleophilic addition while carboxylic acids are acidic and undergo substitution at the acyl carbon.
What is Aldehydes, Ketones and Carboxylic Acids?
Carbonyl compounds contain C=O; aldehydes and ketones undergo nucleophilic addition while carboxylic acids are acidic and undergo substitution at the acyl carbon.
Key formula / rule: Aldehydes are more reactive than ketones towards nucleophilic addition.
Key points
- Compare the reactivity of aldehydes and ketones towards nucleophiles.
- Analyse substituent effects on carboxylic acid strength.
Common exam trap
Predicting nucleophilic substitution instead of addition for aldehydes.
Definitions
- Term
Aldehydes, Ketones and Carboxylic Acids
- Meaning
Carbonyl compounds contain C=O; aldehydes and ketones undergo nucleophilic addition while carboxylic acids are acidic and undergo substitution at the acyl carbon.
- Term
Aldehydes, Ketones and Carboxylic Acids — explanation
- Meaning
The polarised carbonyl carbon is electrophilic, and aldehydes are more reactive than ketones because of less steric hindrance and weaker electron donation. Carboxylic acid acidity comes from resonance in the carboxylate.
Learning objectives
Compare the reactivity of aldehydes and ketones towards nucleophiles.
Analyse substituent effects on carboxylic acid strength.
Formulae
- Key point
Aldehydes are more reactive than ketones towards nucleophilic addition.
- Key point
Carboxylate resonance makes carboxylic acids far more acidic than alcohols.
- Key point
Electron-withdrawing substituents increase carboxylic acid strength.
Prerequisites
CHE-U5-FG-T1-S1-C1
Common mistakes
Predicting nucleophilic substitution instead of addition for aldehydes.
Comparing acid strength without considering substituent effects.
Keywords
Aldehydes
Ketones
Carboxylic
Acids
Practice preview
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