The corrent statement regarding defects is solids in solids is

Options

A. Frenkel defect is usually favored by a very small difference in the sizes of cation and anion
B. Frenkel defect is a dislocation defect
C. Trapping of an electron in the lattice leads to the formation of F-centre
D. Schottky defects have no effect on the physical properties of solids

Explanation

To solve the question regarding the correct statement about defects in solids, we need to analyze each of the given options based on our understanding of solid-state chemistry, specifically focusing on Frenkel defects, Schottky defects, and F-centers.

### Step-by-Step Solution

1. **Understanding Frenkel Defect**:
- A Frenkel defect occurs when an atom or ion leaves its regular lattice position and occupies an interstitial site, creating a vacancy and an interstitial defect simultaneously. This defect is typically found in ionic solids where the size difference between cations and anions is significant.
- **Analysis of Option 1**: "Frenkel defect is usually favored by a very small difference in the size of cation and anion." This statement is incorrect. Frenkel defects are favored by a larger size difference, not a small one.

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