Which of the following two are isostructural? 

1. XeF₂, and IF₂^-

2. NH₃, and BF₃

3. CO₂, and SiO₂

4. PCl₅, and IF₅

Which one of the following species does not exist?

1. ${\mathrm{Be}}_2^{+}$

2. Be₂

3. B₂

4. N₂

In a regular octahedral molecule MX₆, the number of X-M-X bonds at 180$°$is-

1. 3

2. 2

3. 6

4. 4

The correct order of increasing bond angles in the following species is

1. Cl₂O < ClO₂ < ${\mathrm{ClO}}_2^{-}$

2. ClO₂ < Cl₂O < ${\mathrm{ClO}}_2^{-}$

3. Cl₂O < ${\mathrm{ClO}}_2^{-}$ < ClO₂  

4. ${\mathrm{ClO}}_2^{-}$ < ClO₂ < Cl₂O 

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

1. SF₄

2. ${\mathrm{I}}_3^{-}$

3. ${\mathrm{SbCl}}_5^{2-}$

4. PCl₅

In BrF₃ molecule, the lone pairs occupy equatorial positions to minimize:

In which of the following pairs, the two species are isostructural?

1. ${\mathrm{SF}}_4 \mathrm{and} {\mathrm{XeF}}_4$

2. ${\mathrm{SO}}_3^{2-} \mathrm{and} {\mathrm{NO}}_3^{-}$

3. ${\mathrm{BF}}_3 {\mathrm{NF}}_3$

4. ${\mathrm{BrO}}_3^{-} \mathrm{and} {\mathrm{XeO}}_3$

In which one of the following molecules, the central atom said to adopt sp² hybridisation ?

1. BeF₂

2. BF₃

3. C₂H₂

4. NH₃

According to molecular orbital theory, arrange the nitrogen species in each list in ascending order of bond order:

1. ${\mathrm{N}}_2^{-} < {\mathrm{N}}_2 < {\mathrm{N}}_2^{2-}$

2. ${\mathrm{N}}_2^{2-} < {\mathrm{N}}_2^{-} < {\mathrm{N}}_2$

3. ${\mathrm{N}}_2 < {\mathrm{N}}_2^{2-} <\hspace{0.17em}{\mathrm{N}}_2^{-}$

4. ${\mathrm{N}}_2^{-} < {\mathrm{N}}_2^{2-} < {\mathrm{N}}_2$