Which of the two species, NO₃⁻ or H₃O⁺, has the correctly described properties listed below?

1.	Isostructural with the same hybridization for the central atom.
2.	Isostructural with different hybridization for the central atom.
3.	Similar in hybridization for the central atom with different structures.
4.	Dissimilar in hybridization for the central atom with different structures.

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

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

1.		2.
3.		4.

Which of the following pairs of oxygen species and their magnetic behaviour is correct?

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⁺  

Which orbital does the additional electron occupy when O₂ is converted to the O₂⁻ ion?

Which of the following compounds is electron deficient?

1. BaCl₂

2. BCl₃

3. CCl₄

4. PCl₅

Which of the following species contains a dπ–pπ bond?

1. $C{O}_3^{2-}$

2. $P{O}_4^{-3}$

3. $N{O}_3^{-}$

4. $N{O}_2^{-}$

The compound that forms linear polymer due to H-bond is:

How many antibonding electron pair(s) is/are present in the \(O_{2}^{2-}\) ion?