Answer
a. dispersion forces.
b. dispersion forces.
c. dispersion force and dipole-dipole forces
d. dispersion force and dipole-dipole forces and hydrogen bonds are present
Work Step by Step
a. Only dispersion forces are present in krypton as it has no polarity and no hydrogens.
b. Only dispersion forces are present in nitrogen as it has no polarity and no hydrogens.
c. In Carbon monoxide, polar bond exists between C and O. Hence dispersion force and dipole-dipole forces are present in CO.
d. In Hydrogen flouride, a polar bond exists between H and F. The molecule also has hydrogen bonds. Hence dispersion forces, dipole-dipole forces and hydrogen bonds are present in HF.
