2021 HydrocarbonsAddition Reactions of Alkenes – Peroxide Effect Medium Question 18 of 75 in Hydrocarbons

The major product of the following chemical reaction is: $(CH_3)_2CH-CH=CH_2+HBr\xrightarrow{(C_6H_5CO)_2O_2}$ ?

A $(CH_3)_2CH-CH_2-CH_2-O-COC_6H_5$
B $(CH_3)_2CH-CH(Br)-CH_3$
C $(CH_3)_2CBr-CH_2-CH_3$
D $(CH_3)_2CH-CH_2-CH_2-Br$

The answer is D.

Solution

$(CH_3)_2CH-CH=CH_2 + HBr \xrightarrow{(C_6H_5CO)_2O_2} (CH_3)_2CH-CH_2-CH_2-Br$ In the presence of peroxide, HBr adds to unsymmetrical alkenes against Markovnikov's rule (peroxide effect/Kharasch effect).

Concept anti-Markovnikov addition of HBr

Hydrocarbons in past papers

75 questions from this chapter have appeared across 26 exam years.