NTA Abhyas JEE Main2020ChemistryHaloalkanes and HaloarenesPractice
Which of the following statement is correct for the reactivity in S N 2 reaction?
Options
- Ais more reactive than
- Bis more reactive than
- Cis more reactive than
- Dis more reactive than
Correct answer
B. is more reactive than
Step-by-step solution
The electronegativity order of hybridized carbons is s p > s p 2 > s p 3 . So in an allylic halide, such as C H 2 = C H - C H 2 - I , the alpha carbon is much more partially positive than the alpha carbon in C H 3 - C H 2 - C H 2 I . Therefore, the attacking nucleophile will be attracted to the alpha carbon more in the allylic halide compound than in the primary halide. Hence, allylic halides tend to follow S N 2 pathways more than primary halides.