Question

Which one of the following occurs by an addition elimination mechanism?

• A. Toluene, Br${}_2$, FeBr${}_3\to$ $\rho$-bromotoluene
• B. Benzene, HNO${}_3$, H${}_2$SO${}_4\to$ nitrobenzene
• C. Benzene, CO, HCl, AlCl${}_3$, CuCl $\to$ benzaldehyde
• D. 2, 4-dinitrochlorobenzene, NaOH, heat, then H${}^{+}\to$ 2, 4-dinitrophenol

Answer 1

The correct option is D 2, 4-dinitrochlorobenzene, NaOH, heat, then H${}^{+}\to$ 2, 4-dinitrophenol

The reaction in option D proceeds by addition elimination reaction or nucleophilic substitution reaction. First the nuclophile (hydroxide ion) is added and then the chloride ion is eliminated. This reaction is possible due to presence of two electron withdrawing nitro groups.