Identify the correct statements from the following. (1) The dipole moment of $\mathrm{CO}_2$ and $\mathrm{BF}_3$ is zero. (2) The dipole moment of $\mathrm{NF}_3$ is higher than the dipole moment of $\mathrm{NH}_3$. (3) The dipole moment of $\mathrm{HI}$ is lower than the dipole moment of $\mathrm{HCl}$.

1 . The $\mathrm{BF}_3$ molecule has a symmetrical trigonal planar geometry, the moment of any two B-F dipoles is equal in magnitude but opposite in direction to the moment of the $\mathrm{BF}_3$ molecule is zero. Same as $\mathrm{CO}_2$. 2. In $\mathrm{NH}_3, \mathrm{~N}$ is more electronegative than $\mathrm{H}$ so, $\mathrm{N}$ pulls the electrons from $\mathrm{H}$ towards itself so, the direction of moment due to the $\mathrm{N}-\mathrm{H}$ bonds is in the same direction as that of the lone pair of electrons on nitrogen.
But in case of $\mathrm{NF}_3, \mathrm{H}-\bullet$ [Ione pair] moment is in the opposite direction to the $\mathrm{N}-\mathrm{F}$ bond moments. Thus, has smaller net dipole moment. 3. $\because$ Size of $\mathrm{I}$-atom is more than of CI-atom and electronegativity of I-atom is less than of CI-atom. Hence, HI has Iower dipole-moment than HCI.