Question

Calculate the percentage of compounds obtained by monobromination of isobutene. The relative reactivity of 1º, 2º, 3º H atoms to bromination is 1: 82: 1600.

Answer 1

Reactivity order of bromination = 3° : 2° : 1° = 1600 : 82 : 1  

(A) is obtained from the reaction of none equivalent 1° H atoms.

(B) is obtained from the reaction of one 3° H atoms

Percentage of (A) (isobutyl bromide) 9 x 100/1609 = 0.56%

Percentage of (B) (tert-butyl bromide) = 1600 x 100/1609 = 99.4%

Ratio = 177.7:1

Formation of t-Butyl bromide is 177.7 times to that of Isobutyl bromide.

Relative amount  9 x 1

1600 x 1 = 1600.0

Total = 1609.0