Question

The reaction of phenol with chloroform in presence of dilute sodium hydroxide finally introduces which one of the following functional groups?

• A. $-COOH$
• B. $-CHC{l}_2$
• C. $-CHO$
• D. $-C{H}_{2}Cl$

Answer 1

The correct option is C $-CHO$

This is the wordy version of what is referred to as orthoformylation of phenol via a dichlorocarbene intermediate.
In popular parlance, this is the Reimer-Tiemann reaction.

Some of you might know that the mechanism proceeds through the introduction of $CHC{l}_2$ at
the ortho position but the problem statement says "finally introduces which one of... ".
Hence, the answer.