Provide explanations for the following:
a. Methanol, CH₃OH, has a much higher boiling point than methyl mercaptan, CH₃SH.
b. Carbon monoxide has slightly higher melting and boiling points than N₂.
c. The ortho isomer of hydroxybenzoic acid [C₆H₄(OH)(CO₂H)] has a much lower melting point than the meta and para isomers.
d. The boiling points of the noble gases increase with atomic number.
e. Acetic acid in the gas phase has a significantly lower pressure (approaching a limit of one half) than predicted by the ideal gas law.
f. Mixtures of acetone and chloroform exhibit significant negative deviations from Ranoult’s law, which states that the vapor pressure of a volatile liquid is proportional to its mole fraction. For example, an equimolar mixture of acetone and chloroform has a lower vapor pressure than either of the pure liquids.
g. Carbon monoxide has a greater bond-dissociation energy (1072 kJ/mol) than molecular nitrogen (945 kJ/mol)

a. BP of methanol is higher due to strong inter-molecular forces. The bonding becomes harder to break and takes up more energy.

b. The dipole of carbon monoxide is permanent whereas that of nitrogen is not. This higher BP and MP is due to the reason that permanent dipoles are stronger than those that have been induced artificially.

c. Under the given scanrio, the MP of the substance increases with the extent of symmetry; the para and meta isomers are more symmetrical than the ortho isomer. Hence, the MP of the former is higher than that of the latter.

d. With the increasing atomic number, the atomic radius increases. The increased atomic radius results in increased dispersion forces, resulting in an increase in the BP.

e. The ideal gas law has a number of assumptions that go into its formulation. On the basis of those assumptions, all those gases that produce evidence of a near-to-ideal-behavior are the ones that entail non-polar molecules. For instance, hydrogen, nitrogen and oxygen are close to ideal. On the other hand, acetic acid vapors contain molecules whihc are quite larger. Hence, it deviates from the ideal gas laws. Simply speaking, "ideal gas law" is usually for "ideal gases" only, as indicated by the name.

f. The application of this law is for ideal gases only. For non-ideal gases, there are two types of deviations from Ranoult's Law: positive and negative.   In non-ideal cases, the actual vapor pressure may be greater (positive dev) or smaller (negative dev; case of acetone and chloroform mixture). The underlying reason behind a negative deviation is that of the inter-molecular attraction; the attraction between unlike molecules has a tendency to overwhelm that between the like molecules. This is the reason.

g. Since CO has a permanent dipole as greater energy is required to break the intermolecular forces of attraction, it has a greater energy for bond-dissociation.

c (diamond),

sio2 (quartz)