Chemistry

Question Analysis
This question involves the distinction between physical properties of covalent compounds and ionic compounds.

Key Concept Explanation
Covalent compounds generally have lower melting and boiling points than ionic compounds because the intermolecular forces between molecules are relatively weak. They also exhibit poor electrical conductivity and typically exist as discrete molecules.

Option Analysis
Recall the properties of covalent compounds: low melting and boiling points, poor electrical conductivity, and existence as discrete molecules.
Evaluate each option:
Option A (High melting and boiling points): Incorrect. This is a characteristic of ionic compounds, not covalent compounds. 
Option B (Conductivity in the molten state): Incorrect. Conductivity requires mobile charged particles. Covalent compounds do not form ions in the molten state, so they cannot conduct electricity. This is a property of ionic compounds. 
Option C ...