Trichloromethane $\left({\mathrm{CHCl}}_3,\right.$ also called chloroform $)$ has a larger dipole moment than $\mathrm{CF}{\mathrm{Cl}}_3$.  Which property can explain this fact?

In $\text{CHC}{\text{l}}_{\text{3}}$ the order of electronegativity of carbon, hydrogen and chlorine is $\text{Cl}>\text{C}>\text{H}$ whereas in $\text{CFC}{\text{l}}_{\text{3}}$ the order of electronegativity is $\text{F}>\text{Cl}>\text{C}$So, due to the different order of electronegativity in these two molecules, their dipole moments are also different.

(structure of $\text{CHC}{\text{l}}_{\text{3}}$ )

(structure of $\text{CFC}{\text{l}}_{\text{3}}$ )

As in the case of $\text{CHC}{\text{l}}_{\text{3}}$ the net dipole moment is the summation of all other dipole moments, it is greater than $\text{CFC}{\text{l}}_{\text{3}}$.

Therefore, the correct option is $1$.