Question

Dry ice (solid $C{O}_2$) is a/an:
A. ionic crystal
B. covalent crystal
C. molecular crystal
D. metallic crystal

Answer 1

Hint: We know that dry ice is the solid form of carbon dioxide. So, it is known that dry ice is in solid form. This dry ice is used as a cooling agent in houses, laboratories, and industries. As we have studied that all solids are packed with strong intermolecular forces likewise dry ice is also bounded by intermolecular forces.

Complete step by step answer:
We must know that this solid dry ice changes its state or sublimates from its original solid form to gas form when the temperature is about $-78C^o$ at 1atmospheric normal pressure.
Thus, at 1 atmospheric pressure, solid dry ice acts as a coolant. And when this dry ice is placed into warm water then a cloud structure is formed.
As solid dry ice is the solid form of carbon dioxide ($C{O}_2)$ which contains a molecule that has a single carbon atom bonded with two oxygen atoms.

Thus, solid dry ice is a molecular crystal as its constituent particles are molecules that are held together by London dispersion forces, dipole-dipole forces, or hydrogen bonds.
Hence, Option C is the correct answer.

Note:
Remember that solids have low melting points.
-Dry ice is used for preserving frozen foods where mechanical cooling is not available.
-Molecular solids are those in which the molecules are held with intermolecular forces.
-Molecular solids have low melting points and do not conduct electricity.