What is the chief product obtained when n -butane is treated with Br2 in the presence of light a

step 1 Guys in this question we asked what is the chief product obtained when n butane So when n Butane

What is the chief product obtained when n -butane is treated...

What is the chief product obtained when $\mathrm{n}$ -butane is treated with $\mathrm{Br}_{2}$ in the presence of light at $130^{\circ} \mathrm{C}$ ? (1) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CHBrCH}_{3}$ (2) $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCH}_{2} \mathrm{Br}$ (3) $\left(\mathrm{CH}_{3}\right)_{3} \mathrm{C}-\mathrm{Br}$ (4) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br}$

What is the chief product obtained when $\mathrm{n}$ -butane is treated with $\mathrm{Br}_{2}$ in the presence of light at $130^{\circ} \mathrm{C}$ ?
(1) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CHBrCH}_{3}$
(2) $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCH}_{2} \mathrm{Br}$
(3) $\left(\mathrm{CH}_{3}\right)_{3} \mathrm{C}-\mathrm{Br}$
(4) $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br}$

Labs

Want to see this concept in action?

NEW

Explore this concept interactively to see how it behaves as you change inputs.

View Labs

Key Concepts

Radical Chain Mechanism

Free radical halogenation proceeds via a chain mechanism with distinct initiation, propagation, and termination steps. Light induces the homolysis of the halogen molecule to generate halogen radicals, which then abstract hydrogen atoms from the alkane to form alkyl radicals. These alkyl radicals react with additional halogen molecules to form the substituted product and regenerate the halogen radical, thus propagating the chain reaction.

Selectivity in Bromination

Bromine radicals are more selective in hydrogen abstraction since they favor formation of more stable radicals, such as secondary radicals over primary ones. This high selectivity arises from the relatively low activation energies required to abstract a hydrogen from a more substituted carbon, resulting in a reaction that yields predominantly one regioisomer.

Regioselectivity in Alkane Substitution

The regioselectivity in alkane halogenation is influenced by differences in bond dissociation energies and the stability of the resulting radical intermediates. Secondary C–H bonds often have lower bond dissociation energies and produce more stable radicals compared to primary C–H bonds, thereby directing the substitution to occur at the secondary carbon.

Transcript

Please give Ace some feedback