STANDARDChemistry-Haloalkanes and Haloarenes

STANDARD Chemistry Elimination Reactions MCQ Question

Type: MCQ-conceptual-Medium-Class 12

Arrange the following alkyl halides in decreasing order of the rate of β-elimination reaction with alcoholic KOH. (i) CH₃—C—CH₂Br | H (ii) CH₃—CH₂—Br (iii) CH₃—CH₂—CH₂—Br

A

(i) > (ii) > (iii)

B

(iii) > (ii) > (i)

C

(ii) > (iii) > (i)

D

(i) > (iii) > (ii)

Correct Answer

Option D

Detailed Explanation

More the number of β-substituents, more stable alkene it will give on β-elimination. Since (i) has two, (iii) has one β-methyl substituent while (ii) has no β-methyl substituent, therefore, reactivity towards β-elimination decreases in the order: (i) > (iii) > (ii).

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