CHEMISTRY · Single correct · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
Two crystalline solids, X and Y, are compared at room temperature. Both are electrical insulators in the solid and molten states. Solid X has a much lower vapor pressure and a far higher melting point than solid Y. Which inference best explains these observations?
(a) Solid X is metallic with a sea of delocalized electrons, while solid Y is ionic; the metallic bonds in X are stronger than the ionic bonds in Y.
(b) Solid X is a molecular solid held together by extensive hydrogen bonding, whereas solid Y is a non-polar molecular solid held together only by London dispersion forces.
(c) Solid X is a covalent network solid with extensive covalent bonding, whereas solid Y is a molecular solid held together only by intermolecular forces.
(d) Solid X is ionic with strong Coulombic attractions, whereas solid Y is molecular with weaker intermolecular forces.