CHEMICAL BONDING JEE

The bond dissociation energy of B–F in BF₃ is 646 kJ mol^-1 whereas that of C–F in CF₄ is 515 kJ mol^–1. The correct reason for higher B–F bond dissociation energy as compared to that of C–F is

• Significant pπ – pπ interaction between B and F in BF₃ whereas there is no possibility of such interaction between C and F in CF₄.

• Lower degree of pπ – pπ interaction between B and F in BF₃ than that

  between C and F in CF₄

• Smaller size of B-atom as compared to that of C-atom

• Stronger bond between B and F in BF₃ as compared to that between C and F in CF₄.

Among the following species which two have a trigonal bipyramidal shape?

(1) NI₃ (2) I₃^– (3) SO₃^2- (4) NO₃^–

• II and III

• III and IV

• I and IV

• I and III

Using MO theory, predict which of the following species has the shortest bond length?

• O₂^–

• O₂^2-

• O₂²⁺

• O₂⁺

Among the following, the species having the smallest bond is :

• NO

• NO⁺

• O₂

• NO^–

The hybridisation of orbitals of N atom in NO₃^–, NO₂⁺, NH₄⁺ are respectively:

• sp², sp³, sp

• sp, sp³, sp²

• sp, sp², sp³

• sp², sp, sp³

Based on lattice energy and other considerations, which one of the following alkali metal chlorides is expected to have the highest melting point?

• RbCl

• LiCl

• KCl

• NaCl

The structure of IF₇ is :

• octahedral

• pentagonal bipyramid

• square pyramid

• trigonal bipyramid

Which of the following has the square planar structure :

• NH₄⁺

• CCl₄

• XeF₄

• BF₄^–

Among the following the maximum covalent character is shown by the compound :

• AlCl₃

• MgCl₂

• FeCl₂

• SnCl₂

The compound of Xenon with zero dipole moment is :

• XeO₃

• XeO₂

• XeF₄

• XeOF₄