MolSynapsequestion bank
MolSynapse / Question bank / Haloalkanes and Haloarenes / SN2 stereochemistry on drawn chiral halides
JEE Main levelOne or more correct optionsDifficulty 2 of 3hx227

The chiral bromide shown reacts with sodium azide in DMF by the SN2 pathway. Select all correct statements.

  1. AThe product has the opposite spatial arrangement at the stereocentre (Walden inversion).
  2. BThe rate is proportional to both the bromide concentration and the azide concentration.
  3. CA planar carbocation forms first, so the azide obtained is racemic.
  4. DIonisation of the C-Br bond is a separate slow step before azide attacks.

Answer: A, B

SN2 on (S)-2-bromooctane is a one-step concerted backside displacement: the rate is first order in bromide and first order in azide, and the stereocentre is inverted, giving the (R)-azide (the priority order azide, hexyl, methyl, H matches Br, hexyl, methyl, H, so the label flips). There is no carbocation, so no racemisation, and there is no separate ionisation step.
Practice Haloalkanes and Haloarenes More on SN2 stereochemistry on drawn chiral halides
Previous questionNext question

More questions on SN2 stereochemistry on drawn chiral halides