Nucleophilic And Electrophilic Substitution Reactions Both Aromatic And Aliphatic

In this reaction, the compound undergoes an electrophilic addition reaction with HBr. The reaction involves a vinyl group (C=CH2), which can undergo Markovnikov's rule for the addition of HBr. According to Markovnikov’s rule, the hydrogen will add to the carbon atom of the double bond that has the greater number of hydrogen atoms, while the bromine will add to the carbon atom that has fewer hydrogen atoms.
Thus, the addition will proceed as follows:
- The proton (H+) will add to the carbon of the double bond that has more hydrogen atoms (CH2 group).
- The bromine (Br) will add to the other carbon (CH) of the double bond.
This leads to the formation of 2-Bromobutane as the major product.

In this reaction, the goal is to synthesize 1-methoxy-4-nitrobenzene, which involves replacing a halogen atom (bromine) with a methoxy group ( ) at the para position to the nitro group. This reaction typically proceeds through an S_N2 mechanism, where sodium methoxide ( ) acts as a nucleophile and replaces the bromine atom. The methoxy group is a strong nucleophile and reacts efficiently with the electrophilic carbon bonded to the bromine in 1-bromo-4-nitrobenzene.
Thus, the most effective reaction is the one in option (A), where 1-bromo-4-nitrobenzene reacts with sodium methoxide to give 1-methoxy-4-nitrobenzene.