The reaction in which a nucleophile replaces already existing nucleophile in a molecule is called nucleophilic substitution reaction. Haloalkanes are substrate in these reactions. In this type of reaction, a nucleophile reacts with haloalkane (the substrate) having a partial positive charge on the carbon atom bonded to halogen. A substitution reaction takes place and halogen atom, called leaving group departs as halide ion. Since the substitution reaction is initiated by a nucleophile, it is called nucleophilic substitution reaction.

It is one of the most useful classes of organic reactions of alkyl halides in which halogen is bonded to sp3 hybridized carbon.

What is the major product when ethyl bromide reacts with AgNO₂?

Nitroethane 

The correct answer is option 1. Nitroethane.

When ethyl bromide (C₂H₅Br) reacts with silver nitrite (AgNO₂), the reaction proceeds via an \(S_N2\) (bimolecular nucleophilic substitution) mechanism.Silver nitrite (AgNO₂) dissociates in solution to form nitrite ions (NO₂⁻) and Ag⁺ ions. Ethyl bromide undergoes nucleophilic substitution where the nitrite ion (NO₂⁻) acts as a nucleophile. The nitrite ion attacks the carbon atom of ethyl bromide, displacing the bromine atom. This results in the formation of nitroethane (CH₃CH₂NO₂) as the major product.