NaOH; H2O NaOH; H2O NaOH; H2O

NaOH; H2O NaOH; H2O NaOH; H2O

Here are the products of the three chemical reactions:

![alt text](https://i.imgur.com/B948q8I.png)

Explanation

The three reactions shown are examples of the base-catalyzed aldol condensation. In this type of reaction, a strong base like sodium hydroxide (NaOH) removes an acidic proton from the alpha-carbon (the carbon adjacent to the carbonyl group) of an aldehyde or ketone. This creates a resonance-stabilized carbanion known as an enolate. The enolate is a strong nucleophile and attacks the electrophilic carbonyl carbon of another aldehyde or ketone molecule, forming a new carbon-carbon bond.

This initial step, called an aldol addition, forms a β-hydroxy carbonyl compound. Under the reaction conditions, this intermediate readily loses a molecule of water (dehydration) to form a highly stable α,β-unsaturated carbonyl compound. This final product is favored due to the conjugation between the newly formed carbon-carbon double bond and the carbonyl group.

1. 3-Hexanone: This is a self-aldol condensation. 3-Hexanone can form two different enolates. The reaction favors the pathway where the enolate forms at the C-4 position and attacks another 3-hexanone molecule. Subsequent dehydration yields the more substituted and thermodynamically stable α,β-unsaturated ketone, 4-ethyl-5-propyl-oct-4-en-3-one.
2. 3,3-Dimethylcyclopentanone + Pivaldehyde: This is a crossed-aldol condensation. A successful crossed reaction occurs because one reactant, pivaldehyde, has no α-protons and cannot form an enolate. It can only act as the electrophile. The ketone, 3,3-dimethylcyclopentanone, is the sole source of the enolate. The enolate of the ketone attacks the aldehyde, and dehydration follows, leading to 2-(2,2-dimethylpropylidene)-3,3-dimethylcyclopentanone.
3. Propiophenone: This is another self-aldol condensation. Propiophenone has only one set of α-protons, on the methylene group (-CH₂-). The base forms the enolate here, which then attacks a second molecule of propiophenone. The final dehydration step is highly favorable because it creates an extensively conjugated system that includes both phenyl rings and the carbonyl group, resulting in 2-methyl-1,3-diphenylpent-2-en-1-one.