The bond in haloarenes is exceptionally resistant to standard nucleophilic substitution ( or ) under — Haloalkanes and Haloarenes Chemistry Question

💡 Solution & Explanation

All statements correctly highlight a barrier to nucleophilic substitution in haloarenes. A) The $sp^2$ carbon has $33\%$ $s$ -character, making it more electronegative and the $C-X$ bond shorter and stronger than an $sp^3$ bond. B) The $+R$ effect leads to resonance structures that literally draw a double bond between C and X, requiring substantially more energy to break. C) Phenyl cations are notoriously unstable because the vacant orbital resides in the plane of the ring and cannot overlap with the perpendicular aromatic pi-system. D) Approaching nucleophiles (which are electron-rich by definition) face severe electrostatic repulsion from the extensive pi-electron density found above and below the planar benzene ring.