Answer:
Step-by-step explanation:
All of the substances listed, CI2, HCl, H2O, and He, exhibit London (dispersion) forces.
London forces are present in all molecules and atoms due to the random fluctuations in electron distribution that create temporary dipoles. However, the strength of London forces depends on the size of the electron cloud and the polarizability of the molecule or atom.
In the case of the substances listed:
CI2 (diatomic chlorine) is a non-polar molecule that exhibits only London forces.
HCl (hydrogen chloride) is a polar molecule that exhibits both London forces and dipole-dipole forces.
H2O (water) is a polar molecule that exhibits both London forces and hydrogen bonding.
He (helium) is a noble gas atom that exhibits only London forces.