If $B-Cl$ bond has a dipole moment,explain why $BCl_3$ molecule has zero dipole moment.

(N/A) Due to the difference in electronegativity between $B$ and $Cl$,the $B-Cl$ bond is polar in nature.
However,the $BCl_3$ molecule is non-polar.
This is because $BCl_3$ has a trigonal planar geometry,which is a symmetrical shape.
In this structure,the individual dipole moments of the three $B-Cl$ bonds are oriented at an angle of $120^{\circ}$ to each other.
These dipole moments cancel each other out,resulting in a net dipole moment of zero.