a. Physical state: Depending on the force of attraction between covalent molecules the bond may be weaker or stronger. Thus covalent compounds exist in gaseous, liquid, and solid forms. Eg. Oxygen-gas; Water-liquid: Diamond-solid.b. Electrical conductivity: Covalent compounds do not contain charged particles (ions), so they are bad conductors of electricity.c. Melting point: Except few covalent compounds (Diamond, Silicon carbide), they have relatively low melting points compared to Ionic compounds.d. Solubility: Covalent compounds are readily soluble in non-polar solvents like benzene (C6H6), carbon tetrachloride (CCl4). They are insoluble in polar solvents like water.e. Hardness and brittleness: Covalent compounds are neither hard nor brittle. But they are soft and waxy.f. Reactions: Covalent compounds undergo molecular reactions in solutions and these reactions are slow.