Each of the following solids show, the Frenkel defect except

Options

A. ZnS
B. AgBr
C. AgI
D. KCl

Explanation

To determine which of the given solids does not exhibit Frenkel defects, we need to understand what a Frenkel defect is and analyze each solid accordingly.

### Step-by-Step Solution:

1. **Understanding Frenkel Defect**:
- A Frenkel defect occurs when an atom or ion leaves its normal lattice site and occupies an interstitial site. This typically happens in ionic solids where the size of the cation and anion is significantly different, allowing the smaller ion to fit into the interstitial spaces.

2. **Analyzing the Given Solids**:
- **A. ZnS (Zinc Sulfide)**:
- ZnS can exhibit Frenkel defects because the cation (Zn²⁺) and anion (S²⁻) have different sizes, allowing Zn²⁺ to occupy interstitial sites.
- **B. AgBr (Silver Bromide)**:
- AgBr can also show Frenkel defects due to the difference in size between Ag⁺ and Br⁻ ions.
- **C. AgI (Silver Iodide)**:
- Similar to AgBr, AgI can exhibit Frenkel defects because of the size difference between Ag⁺ and I⁻ ions.
- **D. KCl (Potassium Chloride)**:
- KCl consists of K⁺ and Cl⁻ ions, which are isoelectronic (both have 18 electrons). The similar size of these ions means that K⁺ cannot easily move to an interstitial site without causing significant distortion in the lattice structure.

3. **Conclusion**:
- Since KCl has isoelectronic ions and their sizes are approximately the same, it does not exhibit Frenkel defects. Therefore, the solid that does not show Frenkel defects is **D. KCl**.

### Final Answer:
The solid that does not show Frenkel defects is **D. KCl**.

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