Stability of the species Li₂, Li₂⁻ and Li₂⁺ increases in the order of:

• Li₂ < Li₂⁺ < Li₂^-

• Li₂⁻ < Li₂⁺ < Li₂ 

• Li₂< Li₂⁻ < Li₂⁺

• Li₂< Li₂⁻ < Li₂⁺

In which of the following pairs the two species are not isostructural?

• CO₃^2- and NO₃^-

• PCl⁺₄ and SiCl₄

• PF₅ and BrF₅

• PF₅ and BrF₅

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

• FeCl₂

• SnCl₂

• AlCl₃

• AlCl₃

The hybridization of orbitals of N atom in NO₃-, NO₂⁺ and NH₄⁺ are respectively

• sp, sp²,sp³

• sp₂ , sp, sp

• sp, sp³ , sp²

• sp, sp³ , sp²

The group having isoelectronic species is

• O^2– , F^–, Na⁺ , Mg²⁺

• O– , F^–, Na, Mg⁺

• O^2–, F^–, Na ,Mg²⁺

• O^2–, F^–, Na ,Mg²⁺

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

• O₂²⁺

• O₂⁺

• O₂⁻

• O₂⁻

277.

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

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

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

• Significant pπ - pπ interaction between B and F in BF whereas there is no possibility of such 3 interaction between C and F in CF₄ 

• Significant pπ - pπ interaction between B and F in BF whereas there is no possibility of such 3 interaction between C and F in CF₄ 

Which one of the following constitutes a group of the isoelectronic species?

Which one of the following pairs of species has the same bond order?

• CN⁻ and NO⁺

• CN⁻ and CN⁺

• O₂⁻ and CN⁻

• O₂⁻ and CN⁻

Which of the following hydrogen bonds is the strongest?

• O – H …… N

• F – H …… F

• O – H ….. O

• O – H ….. O