Test: Preparation & Reaction of Phenols - JEE MCQ

Upon warming with water, these diazonium salts finally hydrolyze to phenols.

This reaction is known as Reimer-Tiemann reaction.

Thus of phenol require
of phenol require

Phenol has active (acidic) hydrogen so it reacts with to give , and not anisole

Phenol when treated with in the presence of non-polar solvent , it gives only o- and -bromophenols instead the trisubstituted products. Reason for the above observation is supression of phenoxide ion in non-polar solvent. Thus, we get only mono substituted products.

Oxidation of phenol by is an example of Elbs persulphate oxidation.

Due to the formation of complex Phenol gives violet colour with neutral

Electron withdrawing group stabilises the benzene ring due to delocalisation of charge.
and are electron donating group and hence decrease the stability of benzene ring is weaker electron withdrawing group than . Hence group more stabilize the phenoxide ion at -position.

is a alcohol and can be prepared by the reaction of benzaldehyde with Grignard reagent .