The pair of species that has the same bond order in the following is:
1. CO, NO⁺
2. NO^–, CN^–
3. O₂, N₂
4. O₂, B₂

The most preferred structure among the following with the lowest energy for SO₃ is: 

1.		2.
3.		4.

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

1. SF₄

2. $B{F}_4^{-}$

3. $N{H}_4^{+}$

4. CH₄

Some of the properties of the two species, $N{O}_3^{-}$ $and$ $H_3{O}^{+}$  are described below. Which one of them is correct?
 

The pairs of species of oxygen and their magnetic behaviours are given below. Which of the following represents the correct description?

1. $\mathrm{O},$ ${\mathrm{O}}_2^{2-}$ - Both paramagnetic
2. ${\mathrm{O}}_2^{-},$ ${\mathrm{O}}_2^{2-}$ - Both diamagnetic
3. ${\mathrm{O}}^{+},$ ${\mathrm{O}}_2^{2-}$ - Both paramagnetic
4. ${\mathrm{O}}_2^{+},$ ${\mathrm{O}}_2$ - Both paramagnetic

Four diatomic species are listed below. Identify the correct order in which the bond order is increasing in them.
1. O₂^– < NO < C₂^2– < He₂⁺  
2. C₂^2– < He₂⁺ < O₂^– < NO  
3. He₂⁺ < O₂^– < NO < C₂^2–
4. NO < O₂^– < C₂^2– < He₂⁺  

During change of $O_2$ to $O_2^{-}$ ion, the electron adds in which one of the following orbitals? $$

1.  $\pi$ $\mathrm{orbital}$ $$

2.  $\sigma *$ $\mathrm{orbital}$ $$

3.  $\sigma$ $\mathrm{orbital}$

4.  $\pi *$ $\mathrm{orbital}$ $$