Which of the following statements are not correct?

A. Phenol is used to prepare analgesic

B. Solubility of phenol in water is more than that of chlorobenzene

C. Phenol is neutralized by sodium carbonate

D. Boiling point of o-nitrophenol is lower than that of p-nitrophenol

Choose the most appropriate answer from the options given below:

C only

The correct answer is option 2. C only.

The incorrect statement among the given options is C. phenol is neutralized by sodium carbonate.

Phenol is actually acidic in nature and reacts with bases to form salts. Sodium carbonate is a base, and it can react with phenol to form a salt, but calling it "neutralization" might be misleading, as neutralization typically refers to the reaction of an acid with a base to form water and a salt. In the case of phenol and sodium carbonate, the reaction would involve the formation of a phenoxide ion and sodium bicarbonate:

\[ \text{C}_6\text{H}_5\text{OH} + \text{NaHCO}_3 \rightarrow \text{C}_6\text{H}_5\text{O}^{-}\text{Na}^{+} + \text{H}_2\text{CO}_3 \]

Let's discuss the other statements and why they are correct.

A. Phenol is used to prepare analgesic drugs:
This statement is correct. Phenol is used in the synthesis of various pharmaceuticals, including analgesic drugs.

B. Solubility of phenol in water is more than that of chlorobenzene:
This statement is correct. Phenol is partially soluble in water due to the presence of the hydroxyl group, allowing for hydrogen bonding with water molecules. On the other hand, chlorobenzene is nonpolar and less soluble in water.

D. Boiling point of o-nitrophenol is greater than that of p-nitrophenol:
This statement is correct. In general, ortho-substituted compounds have higher boiling points than their para-substituted counterparts due to the intramolecular hydrogen bonding between the hydroxyl group and the nitro group in o-nitrophenol.

So, among the statements, statement C is the incorrect one because phenol is acidic and reacts with bases to form salts rather than undergoing a neutralization reaction.