Question

Reaction of one molecule of HBr with one molecule of 1, 3-butadiene at 40⁰C gives predominantly :

• A. 1-Bromo-2-butene under kinetically controlled conditions
• B. 3-Bromobutene under thermodynamically controlled conditions
• C. 1-Bromo-2-butene under thermodynamically controlled conditions
• D. 3-Bromobutene under kinetically controlled conditions

Answer 1

Answer: (C)

1-Bromo-2-butene under thermodynamically controlled conditions

Answer 2

CH2 = CH – CH = CH2 $\underset{40^{0}C}{\overset{\quad HBR\quad}{\rightarrow}}$ CH3 – CH = CH – CH2 – Br (80%) (1,4) Thermodynamically product