Question

What type(s) of intermolecular forces exist between the following pair?
HBr and \[{H_2}S\]
A.Dipole-dipole intermolecular forces
B.Induced dipole interactions
C.Hydrogen bonding
D.None of the above

Answer 1

Hint: We can have many types of intermolecular forces depending on their bonds and caused between the electron of one molecule and proton of another molecule. In all polar molecules, dipole-dipole interaction occurs which is the strongest intermolecular force.

Complete step-by-step answer:
There are two types of hydrogen bonding which have been recognized so far. First is, intramolecular hydrogen bonding which means within the same molecular and second is intermolecular which is between two or more molecules. Due to hydrogen bonding there is an increase in intermolecular aggregation forces which affect the boiling point and solubility of an organic compound.
Intermolecular hydrogen bonding lowers the acidic strength. For example, HBr is weaker than HI and water is weaker than \[{H_2}S\] . The important types of intermolecular forces other than hydrogen bonding are London dispersion forces, dipole-dipole forces, ion-dipole forces and ion-induced dipole interaction.
Intermolecular forces can be described as the distance-dependent forces of either attraction or repulsion which arise between atoms, molecules and ions that are interacting with each other. London dispersion forces arise because of the formation of a temporary dipole due to shifts in electron densities of the molecules.
Dipole-dipole forces are the strongest type of intermolecular forces which arise due to the electrostatic interactions between two or more dipoles or polar molecules. Whereas dipole induced dipole forces arise due to the interaction between a dipole and an uncharged molecule. An ion-induced dipole forces are weak attractive forces which arise when the approach of an ion induces a dipole in an atom or in a nonpolar molecule by disturbing the electronic arrangement in those species.
Therefore, hydrogen bromide and hydrogen sulphide are polar compounds as both of them have a non-zero dipole moment. So, there is a dipole-dipole interaction between this pair.

Hence, the correct options are (A) and (C).

Note: Polar molecules align such that the positive end of one molecule interacts with the negative end of another molecule. Unlike covalent bonding, dipole-dipole interactions create attraction between molecules of a substance or we can say that it is an intermolecular attraction.