Arrange the following compounds in decreasing order of reactivity towards `S_(N^(2))` displacement reaction and give reasons in support of your answer
Arrange the following compounds in decreasing order of reactivity towards `S_(N^(2))` displacement reaction and give reasons in support of your answer.
(a). `C_(2)H_(5)Br,C_(2)H_(5)IC_(2)H_(5)Cl`
(b). `(CH_(3))_(3)CBr,CH_(3)CH_(2)CHBrCH_(3),CH_(3)CH_(3)CH_(2)CH_(2)Br`.
1 Answers
(a). The cleavage of `C-X` bond is linked with bond dissociation enthalpy. It is the order `C-Cl gt C-Br gt C-I`.
this means that it is easiest to cleave `C-I` bond the order of reactivity is
`C_(2)H_(5)-I gt C_(2)H_(5)-Br gt C_(2)H_(5)-Cl`
(b). The cleavage of `C-Br` bond is related to steric hindrance by alkyl group. Lesser the steric hindrance, more is the reactivity. in the light of this, the order of reactivity is:
`CH_(3)CH_(2)CH_(2)CH_(2)Br gt CH_(3)CH_(2) CHBr CH_(3) gt (CH_(3))_(3) CBr`.