Question

Identify the reagent used in Reimer-Tiemann reaction,

• A. \(\text{CHCl}_{3}\), aq.NaOH
• B. \([\text{O}]\), \(\text{I}_{2}/\text{NaOH}\)
• C. \(\text{NaOH}\), \(\text{CO}_{2}\), \(\text{H}^{+}\)
• D. \(\text{NaHCO}_{3}\), Cu

Hint:

Phenol is heated with chloroform and aqueous NaOH, which forms dichlorocarbene.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept
The Reimer-Tiemann reaction introduces a -CHO group at the ortho position of phenol to give salicylaldehyde.

Step 2: Reagents
Phenol is treated with chloroform and aqueous sodium hydroxide at about 340 K, followed by acid.
The base converts \(\text{CHCl}_{3}\) into dichlorocarbene \(:\text{CCl}_{2}\), which attacks the ortho position of the phenoxide ion.

Step 3: Compare the options
\(\text{I}_{2}/\text{NaOH}\) is for the iodoform test, \(\text{NaOH}\) with \(\text{CO}_{2}\) is for the Kolbe reaction, and the last set is not related.

Final Answer:
The reagents are CHCl3 and aqueous NaOH. \[ \boxed{\text{(A) }\text{CHCl}_{3}\text{, aq.NaOH}} \]