Question

The molecule which has zero dipole moment is?
A. $C{{H}_{2}}C{{l}_{2}}$
B. $B{{F}_{3}}$
C. $N{{F}_{3}}$
D. $Cl{{O}_{2}}$

Answer 1

Hint: It’s an inorganic compound. This pungent colorless toxic gas forms white fumes in moist air. It’s an important Lewis acid very used in organic synthesis. It is also a catalyst used in the reaction of alkylation, esterification and condensation reactions.

Complete step by step answer:
First, let’s understand what dipole moment actually is!
When atoms in a molecule share electrons unequally, they create what is called dipole moment. This occurs when one atom is more electronegative than another, resulting in that atom pulling more tightly on the shared pair of electrons, or when one atom has a lone pair of electrons and the difference of electronegativity vector points in the same way. Let me make it a bit simple, Dipole moments occur when there is a separation of charge, this separation of charge can occur between two ionic bonds or between atoms in covalent bonds.

Well, that was just an introduction to dipole moment!
Now, let’s try to define dipole moment significantly!
When two electrical charges, of opposite sign and equal magnitude are separated by a distance, an electric dipole is established. The size of the dipole is measured by its dipole moment$(\mu )$. Dipole moment is measured in Debye units, which is equal to the distance between the charges multiplied by the charge.

Zero dipole moment is the dipole moment between two atoms being zero. It depends on the polarities of individual bonds and the geometry of the atoms. The dipole bonds are equal in magnitude but opposite in nature. The zero dipole moment of $B{{F}_{3}}$ is due to its symmetrical structure. The three fluorine atoms lie at the corners of an equilateral triangle with boron at the centre. The vectorial addition for the dipole moment of the bonds gives a net sum of zero because the resultant for any two dipole moments is equal and opposite of the third.

Therefore, option B is your answer!

Note: The larger the difference in electronegativity, the larger the dipole moment. The distance between the charge separations is also a deciding factor into the size of the dipole moment. The dipole moment is a measure of the polarity of the molecule.