Heavy metal ions `Ag^+` or `Pb^(2+)` decrease `SN^1` reactivity.
They aid ionisation of `RX`.

Options

A. If both `(A)` and `(R )` are true, but `( R)` is the correct explanation of `(A)`
B. If both `(A)` and `( R)` are true, but `(R )` is not the correct explanation of `(A)`.
C. If `(A)` is true but `( R)` is false.
D. If `(A)` is false but `( R)` is true.

Explanation

To solve the question regarding the effect of heavy metal ions like `Ag^+` or `Pb^(2+)` on `SN1` reactivity, we can break down the concepts involved step by step.

### Step-by-Step Solution:

1. **Understanding SN1 Mechanism**:
- The `SN1` (Substitution Nucleophilic Unimolecular) mechanism involves two main steps:
- The first step is the ionization of the alkyl halide (`RX`) to form a carbocation and a halide ion.
- The second step is the nucleophilic attack on the carbocation.

2. **Role of Heavy Metal Ions**:
- Heavy metal ions like `Ag^+` and `Pb^(2+)` are known to interact with halide ions.
- They can stabilize the halide ion, which can facilitate the ionization of the alkyl halide.

3. **Effect on Ionization**:
- When heavy metal ions are present, they can increase the ionization of the alkyl halide (`RX`).
- This is because the metal ions can form complexes with the halide ions, making it easier for the halide to leave and thus promoting the formation of the carbocation.

4. **Stability of Carbocation**:
- The formation of a more stable carbocation is crucial for the `SN1` mechanism.
- If the ionization is facilitated, the resulting carbocation will be more stable, which in turn increases the reactivity of the `SN1` process.

5. **Conclusion**:
- The assertion states that heavy metal ions decrease `SN1` reactivity, which is incorrect.
- The reason states that they aid in the ionization of `RX`, which is correct.
- Therefore, the correct conclusion is that the assertion is false, while the reason is true.

### Final Answer:
- Assertion: False
- Reason: True