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🧪 Chemistry  ·  Haloalkanes & Haloarenes  ·  NEET & JEE

The reaction of chlorobenzene with Cl<sub>2</sub> in the presence of FeCl<sub>3</sub> gives mainly:

Answer: 1,4-dichlorobenzene (para) and 1,2-dichlorobenzene (ortho) as major products.

  • A 1,3-dichlorobenzene (meta), formed because chlorine is a meta director here
  • B Hexachlorobenzene, formed via complete substitution of all six ring positions
  • C Chlorocyclohexane, formed by saturation of the aromatic ring with chlorine
  • D 1,4-dichlorobenzene (para) and 1,2-dichlorobenzene (ortho) as major products

Correct answer: D. 1,4-dichlorobenzene (para) and 1,2-dichlorobenzene (ortho) as major products

Explanation: In chlorobenzene, Cl is ortho/para directing; electrophilic chlorination (Cl₂/FeCl₃) gives predominantly ortho and para products.

SN2: one stepNu-CX-backside attackNuC+ X-Inversion of configuration(Walden inversion)SN1: two stepsCX-slow: leaving group exits+CcarbocationNu-Planar intermediate givesracemisation (both faces attacked)

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.

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