question_answer

Benzene on treatment with a mixture of conc. \[HN{{O}_{3}}\] and conc. \[{{H}_{2}}S{{O}_{4}}\]at \[{{100}^{o}}C\] gives

A)  nitrobenzene

B)  \[m-\]dinitrobenzene

C)  \[p-\]dinitrobenzene

D)   \[o-\]dinitrobenzene

Correct Answer: B

Solution :

At \[{{60}^{o}}C\] (low temperature) mononitration occurs and nitrobenzene is obtained but at \[{{100}^{o}}C\], nitrobenzene further undergoes electrophilic substitution and gives \[m-\]dinitrobenzene (as\[-N{{O}_{2}}\]is a meta-directing group).