To determine which of the given compounds will undergo an SN2 reaction, we need to analyze the structure of each compound and the nature of the nucleophile involved. The SN2 reaction mechanism is characterized by a single concerted step where the nucleophile attacks the electrophilic carbon, leading to the displacement of the leaving group (in this case, a halide).
### Step-by-Step Solution:
1. **Identify the Compounds**:
- The question refers to three compounds, which we need to analyze for their potential to undergo SN2 reactions. Let's denote them as Compound 1 (Methyl Bromide), Compound 2 (Secondary Alkyl Halide), and Compound 3 (Benzyl Chloride).
2. **Analyze Compound 1 (Methyl Bromide)**:
- Methyl bromide has the structure CH3Br.
- The carbon attached to the bromine is a primary carbon, which is less sterically hindered.
- The bromine atom is a good leaving group, and the methyl group allows for an unhindered attack by a nucleophile.
- Therefore, Compound 1 will undergo an SN2 reaction.
3. **Analyze Compound 2 (Secondary Alkyl Halide)**:
- This compound is a secondary alkyl halide, which means the carbon attached to the halogen is bonded to two other carbon atoms.
- Secondary carbons are more sterically hindered, making it difficult for the nucleophile to attack.
- In this case, the nucleophile is likely to act as a base, leading to an elimination reaction (E2) rather than an SN2 reaction.
- Therefore, Compound 2 will not undergo an SN2 reaction.
4. **Analyze Compound 3 (Benzyl Chloride)**:
- Benzyl chloride has the structure C6H5CH2Cl.
- The carbon attached to the chlorine is a primary carbon, similar to methyl bromide, and is also less sterically hindered.
- Furthermore, the benzyl group can stabilize the transition state due to resonance, making it favorable for an SN2 reaction.
- Therefore, Compound 3 will undergo an SN2 reaction.
5. **Conclusion**:
- Based on the analysis, Compounds 1 (Methyl Bromide) and 3 (Benzyl Chloride) will undergo SN2 reactions, while Compound 2 (Secondary Alkyl Halide) will not.
### Final Answer:
Compounds 1 and 3 will undergo SN2 reactions.
