Question

In Kolbe's reaction the reacting substances are

• A. Sodium phenate and CCl₄
• B. Sodium phenate and CO₂
• C. Phenol and CHCl₃
• D. Phenol and CCl₄

Answer 1

The Correct Option is B

Kolbe's reaction involves the electrolysis of a sodium phenate solution in the presence of carbon dioxide \((CO_2)\).
 Sodium phenate is derived from phenol \((\text{C}_6\text{H}_5\text{OH})\) by treating it with sodium hydroxide \((NaOH)\). When sodium phenate is electrolyzed, it undergoes decarboxylation in the presence of CO₂, resulting in the formation of sodium salicylate.
The reaction can be represented as follows:
\(2 \text{C}_6\text{H}_5\text{ONa} + 2 \text{CO}_2 \rightarrow 2 \text{C}_7\text{H}_5\text{O}_3\text{Na} + \text{O}_2\)
This reaction is an important step in the synthesis of salicylic acid and related compounds.
Therefore, the correct reacting substances in Kolbe's reaction are sodium phenate and CO₂ (option B).

Answer 2

Correct answer: Sodium phenate and CO₂ 

Explanation:

In Kolbe's reaction, sodium phenate (the sodium salt of phenol) reacts with carbon dioxide under heat and pressure to form salicylic acid (o-hydroxybenzoic acid).

 

Reaction:

C₆H₅ONa + CO₂ → o-HOC₆H₄COONa → (on acidification) → o-HOC₆H₄COOH

• This is an electrophilic substitution reaction.
• It is used in the industrial preparation of salicylic acid.

Thus, the correct pair of reacting substances is Sodium phenate and CO₂.

Answer 3

In Kolbe's reaction, the reacting substances are sodium phenate and CO₂.

Explanation:

• Kolbe's reaction, also known as the Kolbe-Schmitt reaction, is a carboxylation chemical reaction that proceeds by heating sodium phenate (the sodium salt of phenol) with carbon dioxide under pressure.
• The reaction results in the formation of salicylic acid (2-hydroxybenzoic acid).

The overall reaction is:

C₆H₅ONa + CO₂ -> o-HOC₆H₄COONa

o-HOC₆H₄COONa + H⁺ -> o-HOC₆H₄COOH

Where o-HOC₆H₄COOH is salicylic acid.

Therefore, the correct answer is:

Sodium phenate and CO₂