Question

Which of the following is an amorphous solid ?

• A. Diamond
• B. Graphite
• C. Common salt
• D. Glass

Hint:

Amorphous = no long-range order (e.g., glass, rubber). Crystalline = sharp melting point and long-range order (e.g., NaCl, diamond).

Answer 1

The Correct Option is D

Step 1: Crystalline vs. amorphous.
Crystalline solids have long–range periodic order (regular repeating arrangement of particles). Amorphous solids lack long–range order and are often called “supercooled liquids.”
Step 2: Analyze options.
Diamond and graphite are crystalline allotropes of carbon (well-defined lattices).
Common salt (NaCl) is ionic and crystalline (face-centred cubic lattice).
Glass has no long-range periodic arrangement — it is amorphous.
Step 3: Conclusion.
Therefore, the amorphous solid among the options is glass (D).