Arrange the following: CH_(3)CH_(2)CH_(2)Cl (I), CH_(3)CH_(2)-CHCI-CH_(3) (II), (CH_(3))_(2)CHCH_(2)CI (III) and (CH_(3))_(3) C-CI (IV) in order of decreasing tendency towards S_(N)2 reactions

Arrange the following: CH_(3)CH_(2)CH_(2)Cl (I), CH_(3)CH_(2)-CHCI-CH

1.	Arrange the following: CH_(3)CH_(2)CH_(2)Cl (I), CH_(3)CH_(2)-CHCI-CH_(3) (II), (CH_(3))_(2)CHCH_(2)CI (III) and (CH_(3))_(3) C-CI (IV) in order of decreasing tendency towards S_(N)2 reactions
Answer» `I gt III gt II gt IV` `III gt IV gt II gt I` `II gt I gt III gt IV` `IV gt III gt II gt I` Solution :The decreasing ORDER of reactivity towards `S_(N)2` REACTION is `underset((I))(CH_(3)CH_(2)CH_(2)Cl) gt underset((III))((CH_(3))_(2)CHCH_(2)Cl) gt underset((II))(CH_(3)CH_(2)CHClCH_(3)) gt underset((IV))((CH_(3))_(3)C Cl)` This is because of increasing steric hindrance.