Question

Reaction of one molecule of HBr with one molecule of 1, 3-butadiene at 40°C gives predominantly

(a) 1-bromo-2-butene under kinetically controlled conditions

(b) 3-bromobutene under thermodyaamically controlled conditions 

(c) 1-bromo-2-butene under thermodynamically controlled conditions

(d) 3-bromobutene under kinetically controlled conditions

Answer 1

Correct Option (c) 1-bromo-2-butene under thermodynamically controlled conditions

Explanation:

Under mild conditions (temprature ≈ - 80°C) kinetic product is the 1, 2-addition product and under vigorous conditions,. (temp. ≈ 40°C) thermodynamic product is the 1 , 4-addition product. Thus, 1-bromo -2 - butene is the major product under given condition.