The mechanism of the nucleophilic substitution reaction between bromoethane CH3CH2Br and sodium hydroxide NaOH is an SN2 Substitution Nucleophilic Bimolecular reaction. Here's a step-by-step description of the mechanism:1. Sodium hydroxide NaOH dissociates into a sodium cation Na+ and a hydroxide anion OH- . The hydroxide anion acts as a nucleophile in this reaction.2. The nucleophile OH- approaches the electrophilic carbon atom the one bonded to the bromine in bromoethane from the side opposite to the leaving group Br- . This is because the nucleophile must attack the electrophilic carbon in a way that allows for the simultaneous breaking of the carbon-bromine bond.3. As the hydroxide anion approaches the electrophilic carbon, it forms a partial bond with the carbon atom, while the carbon-bromine bond starts to break. This results in a transition state where the carbon atom is partially bonded to both the hydroxide anion and the bromine atom. The transition state is a high-energy state and is short-lived.4. The carbon-bromine bond breaks completely, and the bromide ion Br- is released as a leaving group. The hydroxide anion is now fully bonded to the carbon atom, forming ethanol CH3CH2OH .5. The sodium cation Na+ associates with the bromide ion Br- to form sodium bromide NaBr , which is a byproduct of the reaction.Overall, the reaction can be represented as:CH3CH2Br + NaOH CH3CH2OH + NaBrIn summary, the mechanism of the nucleophilic substitution reaction between bromoethane and sodium hydroxide is an SN2 reaction, involving a direct attack of the hydroxide anion on the electrophilic carbon atom, simultaneous breaking of the carbon-bromine bond, and formation of ethanol and sodium bromide as products.