Cannizzaro's reaction is an example of

Options

A. Disproportionation reaction
B. Substitution reaction
C. Elimination reaction
D. Addition reaction

Explanation

**Step-by-Step Solution:**

1. **Understanding Cannizzaro's Reaction**: Cannizzaro's reaction is a chemical reaction that occurs in aldehydes that do not have alpha hydrogens. This reaction involves the simultaneous oxidation and reduction of aldehydes in the presence of a strong base, typically sodium hydroxide (NaOH) or potassium hydroxide (KOH).

2. **Reactants**: The reaction typically involves two moles of an aldehyde, such as formaldehyde (HCHO), which lacks alpha hydrogens.

3. **Reaction Mechanism**:
- In the presence of a strong base, one mole of the aldehyde is oxidized to a carboxylate ion (e.g., formate ion, HCOO⁻), while the other mole is reduced to an alcohol (e.g., methanol, CH₃OH).
- The overall reaction can be represented as:
\[ 2 \text{HCHO} + \text{OH}^- \rightarrow \text{CH}_3\text{OH} + \text{HCOO}^- + \text{Na}^+ \]
- Here, the sodium ion (Na⁺) combines with the carboxylate ion to form sodium formate (the sodium salt of the carboxylic acid).

4. **Products**: The products of Cannizzaro's reaction are:
- An alcohol (e.g., methanol)
- A carboxylate salt (e.g., sodium formate)

5. **Classification of Reaction**: Cannizzaro's reaction is classified as a disproportionation reaction, which is a specific type of redox reaction where a single substance is both oxidized and reduced simultaneously.

6. **Conclusion**: Therefore, Cannizzaro's reaction is an example of a disproportionation reaction involving aldehydes without alpha hydrogens, resulting in the formation of an alcohol and a carboxylate salt.

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