Which of the following structures is the most preferred and hence of lowest energy of SO₃ ? 

In which of the following pairs, both the species are not isostructural?

• SiCl_4.PCl₄⁺

• Diamond, carbide

• NH₃, PH₃

• NH₃, PH₃

In which of the following pairs of molecules/ions, the central atoms have sp² hybridization?

• NO₂^- and NH₃

• BF₃ and NO₂^-

• NH₂^- and H₂O

• NH₂^- and H₂O

Which one of the following species does not exist under normal conditions?

• Be₂⁺

• Be₂

• B₂

• B₂

In which one of the following species the central atom has the type of hybridisation which si not the same as that present in the other three? 

• SF4

• I₃^-

• SbCl₅^2-

• SbCl₅^2-

The correct order of the decreasing ionic radii among the following isoelectronic species is

• Ca²⁺ > K⁺ >S^2- > Cl^-

• Cl^- > S^2- > Ca²⁺ > K⁺

• S^2- > Cl^- > K⁺ > Ca²⁺

• S^2- > Cl^- > K⁺ > Ca²⁺

In which of the following molecules the central atom does not have sp³ hybridisation?

• CH₄

• SF₄

• BF₄^-

• BF₄^-

From the following bond energies:

H-H bond energy: 431.37 kJ mol^-

C=C  bond energy: 606.10 kJ mol-

C- C bond energy: 336.49 kJ mol-

C-H bond energy: 410.50 kJ mol-

Enthalpy for the reaction,


will be

• 1523.6 kJ  mol^-

• -243.6 kJ mol^-

• -1200. kJ mol^-

• -1200. kJ mol^-

According to MO theory which of the following lists ranks the nitrogen species in terms of increasing bond order?

680.

The state of hybridization of C₂, C₃, C₅ and C₆ of the hydrocarbon,


is in the following sequence

• sp, sp³, sp² and sp³

• sp³, sp², sp² and sp

• sp,sp²,sp² and sp³

• sp,sp²,sp² and sp³