Consider the following statements and choose the correct option
(i) Addition of `CdCl_(2)` to the Crystals of `AgCl` will produce cation vacancy
(ii) Additon of `NaCl` to the crystals of `AgCl` would not produce cation vacancy

Options

A. both (i) and (ii) are true
B. Only (i) is true
C. Only (ii) is true
D. Both are false

Answer

To solve the given question, we need to analyze the two statements regarding the addition of `CdCl2` and `NaCl` to the crystals of `AgCl`.

### Step-by-Step Solution:

1. **Understanding the Composition of AgCl**:
- AgCl is composed of silver ions (Ag⁺) and chloride ions (Cl⁻). In the crystal lattice of AgCl, each Ag⁺ ion is surrounded by Cl⁻ ions and vice versa.

2. **Analyzing Statement (i)**:
- The first statement claims that the addition of `CdCl2` to AgCl will produce a cation vacancy.
- When `CdCl2` is added, it dissociates into `Cd²⁺` and `2Cl⁻`.
- The `Cd²⁺` ion has a +2 charge, which means it can replace two `Ag⁺` ions (which each have a +1 charge).
- Therefore, for every `Cd²⁺` ion introduced, two `Ag⁺` ions are replaced, creating a vacancy for one `Ag⁺` ion.
- **Conclusion**: This statement is correct as the introduction of `CdCl2` results in the formation of a cation vacancy.

3. **Analyzing Statement (ii)**:
- The second statement claims that the addition of `NaCl` to AgCl would not produce a cation vacancy.
- `NaCl` dissociates into `Na⁺` and `Cl⁻`.
- The `Na⁺` ion has a +1 charge, which is equal to the charge of `Ag⁺`.
- Thus, when `Na⁺` replaces `Ag⁺`, there is a one-to-one replacement, meaning no vacancies are created.
- **Conclusion**: This statement is also correct as the introduction of `NaCl` does not create any cation vacancies.

4. **Final Conclusion**:
- Both statements (i) and (ii) are correct. Therefore, the correct option is that both statements are true.

### Final Answer:
Both statements are correct.