Sublimation is a process in which a solid :

Options

A. changes into another allotropic form
B. changes into liquid form
C. changes into vapour form
D. None of the above

Answer

**Step-by-Step Solution:**

1. **Understanding Sublimation**: Sublimation is a phase transition where a solid changes directly into a gas without passing through the liquid phase.

2. **Identifying the Process**: In sublimation, the solid absorbs heat energy, which allows its particles to gain enough energy to overcome intermolecular forces and escape into the gas phase.

3. **Examples of Sublimation**: Common examples of substances that undergo sublimation include dry ice (solid carbon dioxide) and camphor. When heated, these solids transition directly into vapor.

4. **Analyzing the Options**: The question provides four options, and we need to identify which one correctly describes the sublimation process. The correct description is that the solid changes into vapor form.

5. **Conclusion**: Therefore, the correct answer to the question "Sublimation is a process in which a solid:" is that it "changes into vapor form."

**Final Answer**: Sublimation is a process in which a solid changes into vapor form.

---