Q.What type of defect can arise when a solid is heated? Which physical property is affected by it and in what way?

When a solid is heated, some particles leave their lattice sites, creating vacancy defects (in ionic solids, Schottky defects). As temperature rises the number of such vacancies increases. Because sites are now empty while the volume is unchanged …

Step 1 – Defect produced on heating.

On heating, thermal energy lets some constituent particles leave their normal lattice positions, generating vacancy defects. In ionic solids this appears as the Schottky defect (equal cation and anion vacancies).

Step 2 – Effect of temperature.

The number of these vacancies increases with temperature — more sites are left empty as the solid gets hotter.

Step 3 – Property affected. …

Identify heating $\to$ vacancy/Schottky defect, note vacancy count rises with temperature, and link empty s …

• Saying density increases — vacancies mean fewer particles in the same volume, so density falls.
• Naming Frenkel defect; heating primarily promotes vacancy/Schottky defects (Frenkel is displacement, den …