Question

which of the following is a possible product in the above reaction?
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Answer 1

CH₃ - CH₂ - CH₂ - Br (1 - bromopropane) is a possible product in the above reaction. Hence, option (1) is correct.

• The given reaction can be completed as follows, following the anti-Markovnikoff rule :

CH₃ - CH = CH₂ + HBr + benzoyl peroxide + hv  → CH₃ - CH₂ - CH₂Br

• The anti - Markovnikoff rule follows the principal of "rich gets poorer, and poor gets richer".

• This rule states that when an alkene or an alkyne reacts with a halo acid (HX) in the presence of a peroxide, the H⁺ ion from the acid gets attached to unsaturated carbon containing lesser number of hydrogen atoms (poor gets richer), and the X⁻ ion gets attached to the carbon containing more number of hydrogen atoms (rich gets poorer).

• In the above reaction, the reactant is an alkene, propene.

• In presence of benzoyl peroxide, the H⁺ ion from HBr attacks the second double bonded carbon atom containing one hydrogen, and the Br⁻ ion attacks the first double bonded carbon atom containing two atoms of hydrogen.

• Thus, the product formed is CH₃ - CH₂ - CH₂Br (1-bromopropane).