question_answer

When phenol is treated with \[{{D}_{2}}S{{O}_{4}}/{{D}_{2}}O,\]some of the hydrogens get exchanged. The final product in this exchange reaction is

A)

B)

C)      

D)

Correct Answer: B

Solution :

In acidic medium, phenol exists in the following resonating structures. Since, o/p-positions are electron rich sites, so electrophile will attack on these sites, i.e. hydrogen of these sites get exchanged by D (deuterium). Hence, the final product of the reaction is which is formed as: