In the Reimer-Tiemann reaction, phenol is treated with chloroform and aqueous sodium hydroxide to form an intermediate 'X', which upon alkaline hydrolysis and subsequent acidification yields salicylaldehyde. Identify the electrophile involved in this reaction and the nature of intermediate 'X'.

Step-by-step solution

In the Reimer-Tiemann reaction, phenol is treated with chloroform ( CHCl ₃ ) and aqueous NaOH . The base removes a proton from chloroform, followed by the loss of a chloride ion to generate dichlorocarbene ( : CCl ₂ ), which acts as the electrophile. The dichlorocarbene attacks the highly reactive phenoxide ion at the ortho position to form an intermediate. According to NCERT, this intermediate is a substituted benzal chloride (specifically, an ortho-dichloromethylphenoxide ion). Subsequent alkaline hydrolysis of t