Among the given species, the isostructural pair is: 

1. $\mathrm{NF}_3 \text { and } \mathrm{BF}_3$
2. $\mathrm{BF}_4^{-} \text {and } \mathrm{NH}_4^{+}$
3. $\mathrm{BCl}_3 \text { and } \mathrm{BrCl}_3$
4. $\mathrm{NH}_3 \text { and } \mathrm{NO}_3^{-}$

The molecule among the following having the highest dipole moment is:
1. CO₂
2. HI
3. H₂O
4. SO₂

The hybridization of nitrogen in ${\mathrm{NO}}_2^{+},$ ${\mathrm{NO}}_3^{-}$ and ${\mathrm{NH}}_4^{+}$ respectively is : 
1. sp, sp^3, and sp²
2. sp, sp^2, and sp³
3. sp², sp, and sp³
4. sp², sp^3, and sp

The correct order of the boiling points of $\mathrm{H}_2 \mathrm{O}, \mathrm{HF}, \text{ and} \ \mathrm{NH}_3$ is: 

1. HF > H₂O > NH₃

2. H₂O > HF > NH₃

3. NH₃ > HF > H₂O

4. NH₃ > H₂O > HF

In ${\mathrm{PO}}_4^{3-}$ ion, the formal charge on the oxygen atom of the P-O bond is : 

In ${\mathrm{NO}}_3^{-}$ ion, the number of bond pairs and lone pairs of electrons exhibited by nitrogen atom is:

1. 2, 2

2. 3, 1

3. 1, 3

4. 4, 0

Which species lacks tetrahedral geometry?

The number of $\mathrm{\pi }$ bonds and $\mathrm{\sigma }$ bonds in the following structure is :

The species that does not have unpaired electrons is:
 

In which of the following molecule/ion all the bonds are not equal?