MCQs on Polarisation and Fajans Rule

When the cation approaches the anion the net positive charge on the cation attracts the electron cloud of the anion and repels the positively charged nucleus of the anion. Therefore, the electron cloud of the anion gets distorted or bulged towards the cation. This is called polarization of the anion. The power of the cation to distort the anion is known as the polarising power of the cation and the tendency of an anion to get polarised is called polarisability of the anion. In inorganic chemistry, Fajans rule formulated by Kazimierz Fajans was used to predict whether a chemical bond will be covalent or ionic, which depends on the charge on the cation and the relative sizes of the cation and anion.

1. The molecule, which contains sp³d² and p orbitals overlapping in it is

1. PCl₅
2. BrF₅
3. ClF₃
4. IF₇

Answer: (b)

2. Homolytic fission of C-C bond of ethane (C₂H₆) which gives an intermediate in which carbon atom is

1. sp³ hybridised
2. sp² hybridised
3. sp hybridised
4. sp³d hybridised

Answer: (b)

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

1. AlCl₃
2. XeF₂
3. Pt(NH₃)₂Cl
4. CH₃MgBr

Answer: (b)

4. Select correct statement

1. Cations with 18 electron shells have greater polarising power than the cations with 8-electron shells.
2. Inner shell electrons have a poor shielding effect on the nucleus and thus electronegativity of the 18 electron shell is increased.
3. CuCl is covalent and NaCl is ionic
4. All are correct statements

Answer: (d)

5. In BrF₃ molecule the lone pairs occupy an equatorial position to minimise

1. lone pair-bond pair repulsion only
2. bond pair-bond pair repulsion only
3. lone pair-lone pair repulsion and lone pair-bond pair repulsion
4. lone pair-lone pair repulsion only

Answer: (d)

6. The hybridisation of phosphorous in POCl₃ is the same as in

1. P in PCl₃
2. S in SF₄
3. Cl in ClF₃
4. B in BCl₃

Answer: (a)

7. If the bond length and dipole moment of diatomic molecules are 1.25A^o and 1.0D respectively, what is the percent ionic character of the bond?

1. 10.66
2. 12.35
3. 16.66
4. 19.33

Answer: (c)

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

1. 6
2. 2
3. 4
4. 3

Answer: (c)

9. Total number of electron pairs in PCl₅, PCl₄⁺ and PCl₆^– are respectively

1. 20, 16, 24
2. 24, 16, 20
3. 16, 20, 24
4. 24, 20, 16

Answer: (a)

10. If the water molecule is linear

1. it would have a very high boiling point
2. it would be highly reactive
3. its dipole moment would be zero
4. it would be highly ionic

Answer: (c)

Also see:

• NEET Chemistry Syllabus
• How to Score 160 Plus in NEET Chemistry
• NEET Chemistry Weightage
• Chemistry Formulas for NEET
• NEET Chemistry MCQs
• NEET Chemistry Important Topics

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