The given reaction is:CH3CH2Br + OH- CH3CH2OH + Br-In this reaction, the hydroxide ion OH- acts as a nucleophile and attacks the electrophilic carbon atom bonded to the bromine atom in the alkyl halide CH3CH2Br . The bromide ion Br- is then displaced as a leaving group, and the product formed is ethanol CH3CH2OH .The mechanism for this reaction is an SN2 Substitution Nucleophilic Bimolecular mechanism. Here's a detailed explanation for this choice:1. The substrate is a primary alkyl halide CH3CH2Br , which is more favorable for SN2 reactions. Primary alkyl halides have less steric hindrance, allowing the nucleophile to approach and attack the electrophilic carbon more easily.2. The nucleophile OH- is a strong and negatively charged nucleophile, which is characteristic of SN2 reactions. Strong nucleophiles favor SN2 reactions because they can readily attack the electrophilic carbon and displace the leaving group.3. The reaction is bimolecular, meaning that the rate-determining step involves both the substrate CH3CH2Br and the nucleophile OH- . In SN2 reactions, the nucleophile attacks the electrophilic carbon at the same time the leaving group Br- departs, resulting in a single concerted step.4. The reaction results in the inversion of stereochemistry at the electrophilic carbon, which is a hallmark of SN2 reactions. Since the nucleophile attacks from the opposite side of the leaving group, the stereochemistry is inverted in the product.In summary, the major product formed in the reaction is ethanol CH3CH2OH , and the mechanism is an SN2 Substitution Nucleophilic Bimolecular mechanism due to the primary alkyl halide substrate, strong nucleophile, bimolecular rate-determining step, and inversion of stereochemistry.