Question

Of the four general types of solids, which one(s) (a) are generally insoluble in water? (b) have very high melting points? (c) conduct electricity as solids?

Short answer

Answer: (a) Covalent and metallic solids are generally insoluble in water. (b) Covalent and ionic solids have very high melting points. (c) Metallic solids conduct electricity as solids.

Step-by-step solution

Identifying the general types of solids

The four general types of solids are ionic, covalent, molecular, and metallic. Each type has specific properties based on the type of bonding and intermolecular forces.

(a) Solids that are generally insoluble in water

Covalent and metallic solids are generally insoluble in water due to their strong bonding. Covalent solids have a network structure of strong covalent bonds. They are insoluble in water as they do not break into ions, which are the dissociation units required for solubility. Metallic solids are composed of positively charged metal ions in a sea of delocalized electrons. Water molecules cannot interact with the metallic lattice to solubilize the solid structure.

(b) Solids with very high melting points

Covalent and ionic solids have very high melting points due to their strong bonding and lattice structures. Covalent solids have a strong network of covalent bonds which require a high amount of energy to break. This results in a high melting point. Ionic solids have a lattice structure of positive and negative ions held together by strong electrostatic forces. The energy required to overcome these forces is very high, resulting in high melting points.

(c) Solids that conduct electricity as solids

Metallic solids conduct electricity as solids due to their unique structure of delocalized electrons. In metallic solids, the delocalized electrons are free to move throughout the lattice structure. These free electrons can conduct an electric current when a voltage is applied, making metallic solids good conductors of electricity in their solid form.