question_answer

Phenol is converted into bake lite by heating it with formaldehyde in the presence of an alkali or an acid. Which statement is true regarding this reaction?

A) The electrophile in both cases is \[C{{H}_{2}}=O\].

B) The electrophile in both cases is \[C{{H}_{2}}=\overset{+}{\mathop{O}}\,H\].

C) The electrophile is \[C{{H}_{2}}=O\]in the presence of an alkali and \[C{{H}_{2}}=\overset{+}{\mathop{O}}\,H\]in the presence of an acid.

D) It is a nucleophilic substitution reaction.

Correct Answer: C

Solution :

[c]: Condensation    of   phenol   with formaldehyde is an electrophilic substitution reaction. Base converts phenol into p hen oxide ion which being more reactive, reacts easily with \[C{{H}_{2}}=O\](a weak electrophile). In presence of an acid, \[C{{H}_{2}}=O\](a weak + electrophile) is protonated to \[C{{H}_{2}}=\overset{+}{\mathop{O}}\,H\](a strong electrophile) which easily reacts with phenol (a weak nucleophile).