1. REACTIONS OF ALDEHYDES, KETONES AND CARBOXYLIC ACIDS

2. Things to Consider
Because the bond strength of the C=O bond (804 kJ/mol) is much stronger than the C=C bond (620 kJ/mol) the carbonyl group is less reactive than the C=C bond found in alkenes.
Because the carbonyl group is very polar, it does undergo many reactions but these are different from those that the alkenes undergo.

3. 1. Combustion
aldehyde or ketone + O2  CO2 + H2O
2. Hydrogenation (a reduction reaction)
Aldehydes produce primary alcohols.
Ketones produce secondary alcohols

4. 3. Oxidation (reaction with KMnO4 or H2Cr2O7)
ONLY ALDEHYDES

5. Qualitative Tests for Aldehydes and Ketones
1. Fehling’s Solution (copper (II) solution)
This is an oxidation reaction in which the blue copper(II) solution will form an orange precipitate if there is a reaction.
aldehydes + Cu2+  carboxylic acid + Cu (s)
blue solution  orange precipitate
ketones + Cu2+  NO REACTION
solution stays blue

6. 2. Tollen’s Reagent (Silver Mirror Test)
Silver ions in ammonia (NH3)
Commercially used to “silver mirror” glass.

7. Reactions of Carboxylic Acids
Organic acids are “weak” acids, therefore they do not completely ionize in water.
1. Neutralization

8. 2. Test for Carboxylic Acids
Reaction with carbonate.
3. Formation of an Ester (reaction with an alcohol)