Assertion : Aromatic aldehydes and formaldehyde undergo Cannizzaro reaction
Reason : Aromatic aldehydes are almost as reactive as formaldehyde.

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states that "Aromatic aldehydes and formaldehyde undergo Cannizzaro reaction." The Cannizzaro reaction is a redox reaction that occurs in aldehydes that do not have alpha-hydrogens.

**Hint:** Recall that the Cannizzaro reaction is favored by aldehydes without alpha-hydrogens.

### Step 2: Identify Aldehydes
Formaldehyde (HCHO) does not have any alpha-hydrogens. Aromatic aldehydes, such as benzaldehyde (C6H5CHO), also lack alpha-hydrogens. Therefore, both formaldehyde and aromatic aldehydes can undergo the Cannizzaro reaction.

**Hint:** Check the structure of the aldehydes to confirm the absence of alpha-hydrogens.

### Step 3: Analyze the Reason
The reason states that "Aromatic aldehydes are almost as reactive as formaldehyde." To evaluate this, we need to consider the reactivity of formaldehyde compared to aromatic aldehydes.

**Hint:** Consider the electrophilicity of the carbonyl carbon in formaldehyde versus aromatic aldehydes.

### Step 4: Compare Reactivity
Formaldehyde is more reactive than aromatic aldehydes because it has no alkyl groups attached to the carbonyl carbon, making it more electrophilic. In contrast, aromatic aldehydes have an aromatic ring, which can donate electron density to the carbonyl carbon, reducing its electrophilicity and, therefore, its reactivity.

**Hint:** Remember that electron-donating groups decrease the electrophilicity of the carbonyl carbon.

### Step 5: Conclusion
Since the assertion is true (both types of aldehydes can undergo the Cannizzaro reaction) and the reason is false (aromatic aldehydes are not as reactive as formaldehyde), we conclude that:

- **Assertion:** True
- **Reason:** False

**Final Answer:** The assertion is correct, but the reason is incorrect.