The incorrect statement about Kolbe's reaction is?

Options

A. Phenoxide ion is less reactive than phenol towards electrophilic aromatic substitution
B. Salicylic acid is formed as the main product
C. Ortho-hydroxybenzoic acid is formed as the main product
D. A weak electrophile `CO_2` is used in this reaction

Explanation

To determine the incorrect statement about Kolbe's reaction, we first need to understand the key aspects of this reaction. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand Kolbe's Reaction
Kolbe's reaction is an electrochemical process where phenol is converted into carboxylic acids. It involves the deprotonation of phenol to form a phenoxide ion, which then reacts with carbon dioxide (CO2) in the presence of an acid (H+) to yield carboxylic acids.

**Hint:** Remember that Kolbe's reaction involves phenol and CO2, leading to the formation of carboxylic acids.

### Step 2: Identify the Reactants and Products
In Kolbe's reaction:
- Phenol (C6H5OH) is treated with sodium hydroxide (NaOH) to form sodium phenoxide (C6H5O⁻Na⁺).
- This sodium phenoxide then reacts with CO2 and H+ to produce carboxylic acids, specifically ortho- and para-hydroxybenzoic acids (salicylic acid being one of them).

**Hint:** Focus on the transformation of phenol to sodium phenoxide and then to carboxylic acids.

### Step 3: Analyze the Statements
Now, let's evaluate the statements given in the question:
1. **A weak electrophile CO2 is used in this reaction.** - This statement is correct; CO2 is indeed a weak electrophile.
2. **Orthohydroxybenzoic acid is formed as the main product.** - This statement is also correct; ortho-hydroxybenzoic acid can be a product.
3. **Salicylic acid is found as the main product.** - This statement is correct as salicylic acid is one of the products formed.
4. **Phenoxide ion is less reactive than phenol towards electrophilic aromatic substitution.** - This statement is incorrect; the phenoxide ion is more reactive than phenol due to its negative charge, which stabilizes the intermediate formed during the reaction.

**Hint:** Compare the reactivity of phenoxide ions and phenol in electrophilic aromatic substitution.

### Step 4: Conclusion
The incorrect statement about Kolbe's reaction is: **"Phenoxide ion is less reactive than phenol towards electrophilic aromatic substitution."** This is because the phenoxide ion, being resonance stabilized and negatively charged, is more reactive than neutral phenol.

**Final Answer:** The incorrect statement is: "Phenoxide ion is less reactive than phenol towards electrophilic aromatic substitution."