Question

Which of the following molecule/ ion has a zero-dipole moment?
(A) $Cl{F_3}$
(B) $IC{l_{{2^ - }}}$
(C) $S{F_4}$
(D) None of these

Answer 1

Hint - To solve this problem we should understand hybridization and the concept behind it and related information including its types and dipole moment and by using this information we will be able to approach the answer.

Complete step by step solution:
> Hybridization: Hybridization is defined as mixing of two atomic orbitals with the same energy levels which results in a new type of orbitals. The intermixing of orbitals is based on quantum mechanics. Atomic orbitals having same level of energy can take part in hybridization
> Types of hybridization:
1) $sp$ Hybridization: when one $s$ and one $p$ orbital is in the same main shell of atom mixed to form new equivalent orbitals, which results in sp hybridized orbitals. It forms linearly having ${180^ \circ }$ .
2) $s{p^2}$ Hybridization: When one $s$ and two$p$ orbitals of the same shell of atom mixed to form $3$ equivalent orbital, which results in $s{p^2}$ hybrid orbitals. It forms trigonal symmetry having ${120^ \circ }$ .
3) $s{p^3}$ Hybridization: When one s and three $p$ orbitals of same shell mixed to form new equivalent orbital, which result in tetrahedral hybridization or $s{p^3}$ having angle ${109.28^ \circ }$
4) $s{p^3}d$ Hybridization: $s{p^3}$ hybridization involves the mixing of $3p$ orbitals and$1d$ orbital to form$5s{p^3}d$ hybridized orbitals of same energy, having trigonal bipyramidal geometry having angle ${120^ \circ }$.
> Dipole moment: Dipole moment arises where there is separation of charges. Dipole moment arises due to difference in electronegativity between two chemically bound atoms. It measures the polarity of chemical bonds between two atoms in a molecule, and also measures the separation of negative and positive charges in a system. It is denoted as ${\delta ^ + }\,{\delta ^ - }$ represents the two electric charges that arise in a molecule.
$IC{l_{{2^ - }}}$ has linear shape with $2$ bond pairs and $3$ lone pairs. It undergoes $s{p^3}d$ hybridization. Two dipole moments of two bonds cancel each other. Hence,$IC{l_{{2^ - }}}$ has zero dipole moment.

Hence, the correct answer is option B. $IC{l_{{2^ - }}}$

Note - The dipole moment of a single bond in a polyatomic molecule is known as the bond dipole moment and it is different from the dipole moment of the molecule as a whole. It is a vector quantity i.e. it has magnitude as well as definite direction. Being a vector quantity. It can also be zero as the two positively acting bond dipoles can cancel each other.
In chemistry, the dipole moment is represented by a slight variation of the arrow angle.it is denoted by cross on the positive centre and arrowhead in the negative center.