Amongst the following, which are true for `S_(N^2)` reaction ? (i) The rate of reaction is independent of the concentration of the nucleophile. (ii) The nucleophile attacks the carbon atom on the side of the molecule opposite to the group being displaced. (iii) The reaction proceeds with simultaneous bond formation and bond rupture.

Options

A. (i), (ii)
B. (i), (iii)
C. (i), (ii), (iii)
D. (ii), (iii)

Explanation

To determine which statements are true regarding the \( S_N2 \) reaction, let's analyze each statement one by one based on the characteristics of the \( S_N2 \) mechanism.

### Step-by-Step Solution:

1. **Understanding the \( S_N2 \) Reaction**:
- The \( S_N2 \) reaction is a bimolecular nucleophilic substitution reaction where a nucleophile attacks an electrophilic carbon atom, leading to the displacement of a leaving group. The mechanism involves a single concerted step where bond formation and bond breaking occur simultaneously.

2. **Analyzing Statement (i)**:
- **Statement**: "The rate of reaction is independent of the concentration of the nucleophile."
- **Analysis**: This statement is **false**. The rate of an \( S_N2 \) reaction depends on both the concentration of the nucleophile and the substrate. The rate law for an \( S_N2 \) reaction is given by \( \text{Rate} = k[\text{Nucleophile}][\text{Substrate}] \). Therefore, the reaction rate is directly influenced by the concentration of the nucleophile.

3. **Analyzing Statement (ii)**:
- **Statement**: "The nucleophile attacks the carbon atom on the side of the molecule opposite to the group being displaced."
- **Analysis**: This statement is **true**. In an \( S_N2 \) reaction, the nucleophile performs a backside attack on the carbon atom, which is opposite to the leaving group. This leads to the inversion of configuration at the carbon center.

4. **Analyzing Statement (iii)**:
- **Statement**: "The reaction proceeds with simultaneous bond formation and bond rupture."
- **Analysis**: This statement is **true**. The \( S_N2 \) mechanism involves a transition state where the nucleophile forms a bond with the carbon atom while the leaving group simultaneously breaks its bond with the carbon. This characteristic is a defining feature of the \( S_N2 \) mechanism.

### Conclusion:
- The true statements regarding the \( S_N2 \) reaction are:
- (ii) The nucleophile attacks the carbon atom on the side of the molecule opposite to the group being displaced.
- (iii) The reaction proceeds with simultaneous bond formation and bond rupture.

### Final Answer:
- The correct statements are (ii) and (iii).