Explain how the stereochemistry of `SN^1` and `SN^2` differs.

Explanation

### Step-by-Step Solution:

1. **Understanding SN1 Reaction**:
- The SN1 reaction is a unimolecular nucleophilic substitution reaction. The rate of this reaction depends only on the concentration of the substrate and not on the nucleophile. This means that the reaction follows first-order kinetics.
- In SN1, a carbocation intermediate is formed after the leaving group departs. This carbocation can be attacked by the nucleophile from either side (front or back).

2. **Stereochemistry of SN1**:
- When the nucleophile attacks the carbocation, it can do so from either the front or the back.
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