Which of the following compounds has difficulty in breaking $\mathrm{C}-\mathrm{X}$ bond?
Which of the following compounds has difficulty in breaking $\mathrm{C}-\mathrm{X}$ bond?
O-nitrochlorobenzene
P - nitrochlorobenzene
m-nitrochlorobenzene
2, 4, 6-trinitrochlorobenzene
Solution
In aryl halide, $\mathrm{X}$ atom is attached with $\mathrm{sp}^2(\mathrm{C})$, the $\mathrm{C}-\mathrm{X}$ bond in aryl halide is shorter than in alkyl halides. This makes $\mathrm{C}-\mathrm{X}$ bond stronger in aryl halides.
Under normal conditions, halobenzene's are inert to nucleophiles. However, Chlorobenzene can be made to react if the experimental conditions are:
1. High temperature and high pressure.
2. In presence of strong electron-withdrawing $\left(-\mathrm{NO}_2\right)$ substituent at ortho and/or para positions.
Thus, $\mathrm{m}-$ nitrochlorobenzene has difficulty in breaking $\mathrm{C}-\mathrm{X}$ bond.