Answer: F > Cl > Br > I (ortho/para directors despite being deactivating).
- A F > Cl > Br > I (ortho/para directors despite being deactivating)
- B I > Br > Cl > F, the reverse order of true ortho/para directing strength
- C Substitution occurring preferentially through the meta position instead
- D Haloarenes failing to undergo electrophilic aromatic substitution entirely
Correct answer: A. F > Cl > Br > I (ortho/para directors despite being deactivating)
Explanation: All halogens are ortho/para directors (lone pair donation by resonance dominates over inductive withdrawal) but deactivating overall. The ortho/para directing power follows F > Cl > Br > I (stronger resonance donation).
SN2 proceeds in a single step with backside attack and inversion of configuration, while SN1 forms a planar carbocation intermediate first, leading to racemisation.
Concept context
Study carbon-halogen compounds: how they are made, how they react via SN1/SN2 and elimination, their stereochemistry, and their environmental impact.