QAIPMT-2010-Ch-1997: NEET 2010 Chemistry - Class 12 AIPMT-2010-Ch-1997 Solution: The correct order of increasing reactivity of C-X bond towards…

The order of reactivity is dependent on the stability of the intermediate carbocation formed by cleavage of C�X bond. The 3� carbocation formed in III will be more stable than its 2� homologue (IV) which in turn will be more stable than arenium ion (I). Moreover, the aryl halide has a double bond character in the C�X bond which makes the cleavage more difficult. On other hand II will be more reactive than I due to presence of electron withdrawing �NO 2 group. C�X bond becomes weak and undergoes nucleophilic substitution reaction So Correct order is I < II < IV < III.