Question

The major product of the following reaction is:
\[C{H_3} - CH = C{H_2} + HBr\xrightarrow{{{{\left( {{C_6}{H_5}CO} \right)}_2}{O_2}}}?\]
A.\[C{H_3} - C{H_2} - C{H_2} - Br\]
B.\[C{H_3}CH\left( {Br} \right) - C{H_3}\]
C.\[BrC{H_2} - CH = C{H_2}\]

Answer 1

Hint: Alkenes are unsaturated hydrocarbons consisting of one or more double bonded carbon atoms. In presence of peroxides the product forms according to anti-markovnikov's rule. It states that the negative part of the reagent should be attacked on the carbon containing more hydrogen atoms.

Complete answer:
Hydrocarbons are the chemical compounds that consist of only carbon and hydrogen atoms. Alkanes, alkenes, and alkynes are the hydrocarbons consisting of carbon and hydrogen atoms. Alkenes are the hydrocarbons consisting of carbon-carbon double bonded atoms. The general molecular formula of alkanes is \[{C_n}{H_{2n}}\] , where n is the number of carbon atoms.
When the addition of reagents to alkenes, in presence of peroxides follows anti-markovnikov rule. It states that the negative part of the reagent attacks on the carbon containing more number of hydrogen atoms. The positive part of the reagent attacks on the carbon containing less number of hydrogen atoms.
Given a molecule is \[C{H_3} - CH = C{H_2}\] , it is a propene. The addition of hydrogen bromide in presence of \[{\left( {{C_6}{H_5}CO} \right)_2}{O_2}\] which is known as benzoyl peroxide.
The bromide ion in hydrogen bromide attacks on the methylene group, and the hydrogen ion attacks on the \[ - CH\] group.
\[C{H_3} - CH = C{H_2} + HBr\xrightarrow{{{{\left( {{C_6}{H_5}CO} \right)}_2}{O_2}}}C{H_3} - C{H_2} - C{H_2}Br\]
Thus, the product is \[C{H_3} - C{H_2} - C{H_2}Br\]

Option A is the correct one.

Note:
In the absence of peroxides like benzoyl peroxide and hydrogen peroxide. The addition of alkenes takes place via markovnikov rule. It states that the negative part of the reagent attacks on the carbon containing less number of hydrogen atoms and the positive part of the reagent attacks on the carbon containing more number of hydrogen atoms. But in presence of peroxides the addition of alkenes takes place via markovnikov rule.