Question

Question: What is the major monobromination product formed by heating each alkane with Br₂ ?

Short answer

Answer

Step-by-step solution

Monobromination

The organic reaction involving the replacement of the most reactive C-H bond by a bromide ion forming a C-Br bond in the presence of thermal energy is known as the monobromination reaction.

Product

Let us consider the bromination of the given alkanes,

a) In 3-ethylhexane, the hydrogen bonded to the tertiary carbon atom is replaced by a bromide ion. This is because of the relative stability of the tertiary carbon and the reactivity of the C-H bond.

Formation of 3-bromo,3-ethylhexane

b) In methyl cyclopropane, the hydrogen atom bonded to the only tertiary carbon atom is replaced to give the following major product.

Formation of bromo-substituted methyl cyclopropane

c) In 2,2-dimethyl butane, the most reactive hydrogen bonded to the secondary carbon atom is replaced by bromide ion.

Formation of 2-bromo,3,3-dimethyl butane