Question

In the following substitution reaction:

• A.
• B.
• C.
• D.

Hint:

In substitution reactions, the leaving group is displaced by a nucleophile, leading to a new product. The order and nature of the nucleophile and leaving group affect the reaction outcome.

Answer 1

The Correct Option is A

Substitution Reaction Analysis:

This problem concerns a substitution reaction, characterized by the exchange of an atom or molecular group for another. To determine the resultant product, the reaction mechanism and involved reagents must be identified.

Common substitution reaction types in organic chemistry include:

• SN1 Reactions: Unimolecular nucleophilic substitution proceeding via a carbocation intermediate, typically observed with tertiary substrates.
• SN2 Reactions: Bimolecular nucleophilic substitution involving direct displacement without intermediates, characteristic of primary and secondary substrates.

The substrate is a benzene ring substituted with two bromine atoms and a nitro group ($NO_2$). Sodium ethoxide ($C_2H_5ONa$) in ethanol ($C_2H_5OH$) acts as a potent nucleophile and base. The electron-withdrawing nitro group enhances the benzene ring's susceptibility to nucleophilic aromatic substitution, particularly at positions ortho and para to it.

In this scenario, one bromine atom will be displaced by the ethoxide group ($OC_2H_5$). Substitution will occur preferentially at the bromine atom most activated by the nitro group. As both bromine atoms are ortho to the nitro group, their activation levels are equivalent. Consequently, the product will feature the ethoxide group replacing one of the bromine atoms.

<p>The product 'P' is: </p>