Polarization and Fajans Rule MCQs

When a cation approaches an anion, the net positive charge of the cation attracts the electron cloud of the anion while repelling the anion’s positively charged nucleus. As a result, the electron cloud of the anion becomes distorted or shifted towards the cation, a process known as polarization. The ability of the cation to distort the anion is referred to as the polarizing power of the cation, while the anion’s tendency to be polarized is called its polarizability. In inorganic chemistry, Fajans’ rule, formulated by Kazimierz Fajans, is used to predict whether a chemical bond will be covalent or ionic, based on the charge of the cation and the relative sizes of the cation and anion.

In the BrF₃ molecule, the lone pairs occupy an equatorial position to minimize

(a) lone pair-bond pair repulsion only
(b) bond pair-bond pair repulsion only
(c) lone pair-lone pair repulsion and lone pair-bond pair repulsion
(d) lone pair-lone pair repulsion only

The molecule that contains both sp³d² and p orbitals overlapping is

(a) PCl₅
(b) BrF₅
(c) ClF₃
(d) IF₇

The hybridization of phosphorus in POCl₃ is the same as in

(a) P in PCl₃
(b) S in SF₄
(c) Cl in ClF₃
(d) B in BCl₃

If the water molecule were linear

(a) it would have a very high boiling point
(b) it would be highly reactive
(c) its dipole moment would be zero
(d) it would be highly ionic

Select the correct statement

(a) Cations with 18 electron shells have greater polarizing power than cations with 8-electron shells.
(b) Inner shell electrons have a poor shielding effect on the nucleus and thus the electronegativity of the 18-electron shell is increased.
(c) CuCl is covalent and NaCl is ionic
(d) All are correct statements

If the bond length and dipole moment of a diatomic molecule are 1.25 Å and 1.0 D respectively, what is the percent ionic character of the bond?

(a) 10.66
(b) 12.35
(c) 16.66
(d) 19.33

Which of the following compounds has a trigonal bipyramidal electron pair geometry with three equatorial positions occupied by lone pairs of electrons?

(a) AlCl₃
(b) XeF₃
(c) Pt(NH₃)₂Cl
(d) CH₃MgBr

The total number of electron pairs in PCl₅, PCl₄⁺, and PCl₆⁻ are respectively

(a) 20, 16, 24
(b) 24, 16, 20
(c) 16, 20, 24
(d) 24, 20, 16

The molecule MLₓ is planar with six pairs of electrons around M in the valence shell. The value of x is

(a) 6
(b) 2
(c) 4
(d) 3

The homolytic fission of the C-C bond in ethane (C₂H₆) produces an intermediate in which the carbon atom is

(a) sp³ hybridized
(b) sp² hybridized
(c) sp hybridized
(d) sp³d hybridized