KBr shows which of the following defects ?

Options

A. Frenkel defect
B. Schottky defect
C. Metal excess defect
D. Metal deficiency

Answer

To determine which defect KBr shows, we can analyze the properties of the ionic compound KBr and the types of defects that can occur in ionic crystals.

### Step-by-Step Solution:

1. **Understanding Ionic Compounds**:
- KBr is an ionic compound composed of potassium ions (K⁺) and bromide ions (Br⁻).

2. **Identifying Ionic Sizes**:
- The sizes of K⁺ and Br⁻ ions are relatively similar. This similarity in size is crucial for determining the type of defects that can occur in the crystal lattice.

3. **Types of Defects**:
- In ionic crystals, defects can be classified mainly into two types: Schottky defects and Frenkel defects.
- **Schottky Defect**: This occurs when equal numbers of cations and anions leave the lattice, creating vacancies. This defect is more likely when the cations and anions are of similar size.
- **Frenkel Defect**: This occurs when a cation leaves its position and occupies an interstitial site, creating a vacancy in its original position. This defect is typically observed when there is a significant size difference between cations and anions.

4. **Application to KBr**:
- Since K⁺ and Br⁻ ions are of similar size, KBr is more likely to exhibit Schottky defects. In this case, equal numbers of K⁺ and Br⁻ ions leave the lattice, maintaining electrical neutrality while creating vacancies.

5. **Conclusion**:
- Therefore, KBr shows Schottky defects.

### Final Answer:
KBr shows Schottky defects.

---