Use the information and data given below to answer the questions (a) to (c):
(a) Which type of intermolecular forces are present in the molecules HF, HCl, HBr and HI?
(b) Looking at the trend of boiling points of HCl, HBr and HI, explain out of dipole-dipole interaction and London interaction, which one is predominant here.
(c) Why is boiling point of hydrogen fluoride highest while that of hydrogen chloride lowest?
(a) Dipole-dipole are present in HCl, HBr, HI and HF; but, in HF along with these Intermolecular hydrogen bonding is also present.
(b)Dipole moment decreases from HCl to HI due to decrease in electronegativity, whereas, from HCl to HI its boiling point increases, hence we can say that London forces are predominant here.
(c) HF has hydrogen bonding as well as the highest electronegativity; hence it has the highest dipole moment as well as the highest boiling point.