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JEE Main levelSingle correct optionDifficulty 2 of 3hx134

In the Reimer-Tiemann reaction, phenol is heated with chloroform and aqueous $NaOH$ to give salicylaldehyde. The electrophile that attacks the phenoxide ring is

Atrichloromethyl cation, $CCl X_{3} X^{+}$
Bdichlorocarbene, $: CCl X_{2}$
Cchlorine radical, $Cl$
Dcarbon tetrachloride

Answer: B

OH X^{-}

removes a proton from

CHCl X_{3}

to give

CCl X_{3} X^{-}

, which loses

Cl X^{-}

to form the electrophilic dichlorocarbene. It attacks the ortho position of phenoxide, and the

- CHCl X_{2}

group is hydrolysed to

- CHO

.

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