`SN^(1)` and `SN^(2)` mechanisms

Explanation

### Step-by-Step Solution for SN1 and SN2 Mechanisms

**Step 1: Definition of SN1 and SN2 Mechanisms**
- **SN1 Mechanism**: This is a nucleophilic substitution reaction that involves a single reactant molecule (unimolecular) in the rate-determining step. The mechanism proceeds through the formation of a carbocation intermediate.
- **SN2 Mechanism**: This is a nucleophilic substitution reaction that involves two reactant molecules (bimolecular) in the rate-determining step. The reaction proceeds via a single transition state without the formation of an intermediate.

**Step 2: Molecularity and Kinetics**
- **SN1**: The molecularity is 1, and it follows first-order kinetics. This means that the rate of the reaction depends only on the concentration of the substrate.
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