1
The correct order of increasing reactivity of [figure] C–X bond towards nucleophile in the following compounds is
- I < II < IV < III
- II < III < I < IV
- IV < III < I < II
- III < II < I < IV
Answer
(1) I < II < IV < III
Solution
I (aryl halide): the C–X bond has partial double bond character due to resonance, so it is the least reactive.
II: the –NO2 groups at ortho and para positions withdraw electrons and stabilise the intermediate, so II is more reactive than I.
III and IV (alkyl halides) are more reactive than aryl halides. III is tertiary and forms the most stable carbocation, so III > IV.
Increasing order: I < II < IV < III
Answer: (1)
AIPMT 2010 (Prelims)