Question

How Identify the most important types of interparticle forces present in the solids of each of the following substances?
a) Ar
b) $C{H_4}$
c) HCl
d) CO
e) HF
f) $NaN{O_3}$
g) $CaC{l_2}$

Answer 1

We all know that the type of intermolecular forces present in a molecule will depend upon the nature of the molecule. Polar molecules or dipoles will have dipole-dipole forces existing between them. While non polar molecules will have induced dipole-induced dipole forces existing between them. Dipole-induced dipole forces exist between a polar and a nonpolar molecule. Hydrogen bonding is a type of dipole-dipole force that occurs when a hydrogen atom is attached to a highly electronegative atom (oxygen, fluorine, nitrogen). Ion-ion forces exist between the ions of opposite charges.
With this knowledge about the interparticle forces, we can easily detect the type of interparticle forces existing between the molecules given in the question.

Complete answer:
a) Ar (we know that Ar is a nonpolar molecule)
Induced dipole induced dipole forces or Van der Waal forces or London forces present.
b) $C{H_4}$(we know that methane is a nonpolar molecule)
Induced dipole induced dipole forces or Van der Waal forces or London forces present.
c) HCl (polar molecule)
Very weak Hydrogen bonding. Along with this dipole-dipole forces also present.
d) CO (polar molecule)
Dipole-dipole, induces dipole-dipole forces and induced dipole-induced dipole forces also present.
e) HF (polar molecule)
Hydrogen bonding. Along with these dipole-dipole, induces dipole-dipole forces and induced dipole-induced dipole forces also present.
f) $NaN{O_3}$ (ionic lattice)
Ion-ion forces present.
g) $CaC{l_2}$ (ionic lattice)
Ion-ion forces present.

Note: We should be clear about our idea about polar and nonpolar molecules. Polar molecules are those molecules which have an unequal distribution of charges while non-polar molecules have an equal distribution of charge. Always keep in this mind, ion-ion interactions exist between ions of opposite charges.