Out of `S_(N^(1))` and `S_(N^(2))` which reaction occurs with (a) inversion of configuration (b) racemisation.

Explanation

To solve the question regarding which reaction occurs with inversion of configuration and which leads to racemization between \( S_N^1 \) and \( S_N^2 \) mechanisms, we can break down the concepts step by step.

### Step-by-Step Solution:

1. **Understanding \( S_N^2 \) Mechanism**:
- The \( S_N^2 \) (bimolecular nucleophilic substitution) mechanism involves a single concerted step where the nucleophile attacks the substrate from the side opposite to the leaving group.
- This results in an inversion of configuration at the carbon atom where the substitution occurs.

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