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Question
A primary alkyl halide would prefer to undergo ______.
Options
SN1 reaction
SN2 reaction
α–Elimination
Racemisation
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Solution
A primary alkyl halide would prefer to undergo SN2 reaction.
Explanation:
SN2 type reactions (i.e. bimolecular nucleophilic substitution) proceed in one step and the rate of reaction depends on concentration of alkyl halide as well as nucleophile i.e. r = k[RX][Nu]. It is a second-order reaction. During SN2 reaction, inversion in configuration occurs (viz. starting with dextrorotatory halide a laevorotatory product is obtained and vice-versa).
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| (II) |  |
| (III) |  |
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| (ii) | \[\begin{array}{cc} \ce{CH3 - CH = CH2 + HBr -> CH3 - CH - CH3}\\ \phantom{............................}|\phantom{}\\ \phantom{.............................}\ce{Br}\phantom{} \end{array}\] |
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| (v) | \[\begin{array}{cc} \ce{CH3 CH2 CH CH3 ->[alc.KOH] CH3 CH = CH CH3}\\ \phantom{}|\phantom{..........................}\\ \phantom{}\ce{Br}\phantom{........................} \end{array}\] |
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|
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OR
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