Among the following which is more reactive toward `AgNO_(3)`?

Options

A.
B.
C.
D.

Explanation

To determine which compound is more reactive toward AgNO₃, we need to analyze the stability of the resulting carbocations after the halide (Br⁻) is removed from each compound. The more stable the carbocation, the less reactive the compound will be. Conversely, the less stable the carbocation, the more reactive the compound will be.

### Step-by-Step Solution:

1. **Identify the Compounds**: We need to analyze the reactivity of four different compounds (let's label them A, B, C, and D) toward AgNO₃.

2. **Remove Br⁻ from Each Compound**: For each compound, we will remove Br⁻ and observe the resulting carbocation:
- **Compound A**: Removing Br⁻ leads to a positive charge on the carbon adjacent to the oxygen. The oxygen can stabilize this positive charge through its +M (mesomeric) effect.
- **Compound B**: After removing Br⁻, a positive charge is formed on a sp² hybridized carbon. The oxygen can donate its lone pair to the ring, resulting in a conjugated system. This compound can become aromatic due to the presence of 6 π electrons in a planar ring, which significantly increases its stability.
- **Compound C**: Similar to B, removing Br⁻ creates a positive charge on a sp² hybridized carbon. However, the resulting structure has 4 π electrons in a cyclic and planar arrangement, making it anti-aromatic. Anti-aromatic compounds are less stable than non-aromatic or aromatic compounds.
- **Compound D**: Removing Br⁻ leads to a carbocation that can be stabilized by hyperconjugation and the +I (inductive) effect from adjacent groups, but it does not achieve the same level of stability as an aromatic system.

3. **Compare Stability of Carbocations**:
- **A**: Stabilized by +M effect from oxygen.
- **B**: Aromatic stabilization (most stable).
- **C**: Anti-aromatic (least stable).
- **D**: Stabilized by hyperconjugation and +I effect, but less than B.

4. **Determine Reactivity**: Since the stability of the carbocation is inversely related to reactivity, the compound that forms the least stable carbocation will be the most reactive toward AgNO₃.
- Compound B, being aromatic, is the most stable and thus the least reactive.
- Compound C, being anti-aromatic, is the least stable and thus the most reactive.

5. **Conclusion**: The compound that is most reactive toward AgNO₃ is **Compound C**.