Classifying solids by crystal structures and properties

Steps:

• Identify P's structure: alternating positive/negative ions in a lattice, indicating giant ionic solid like NaCl.
• Identify Q's structure: continuous network of atoms bonded covalently, indicating giant covalent solid like diamond.
• Compare to first property (giant structure): both P and Q exhibit extended lattices beyond molecules.
• Compare to second property (insoluble in water): ionic solids like P dissolve due to ion hydration; covalent networks like Q do not.

Why D is correct:

• D matches both solids having giant structures (extended lattices) while only Q is insoluble, per solubility rules for ionic vs. covalent network solids.

Why the others are wrong:

• A: Falsely limits both properties to P only, ignoring Q's giant structure.
• B: Incorrectly assigns second property to Q only but first solely to P, overlooking Q's lattice.
• C: Wrongly gives second property to P only, as ionic solids are typically water-soluble.

Final answer: D