Which one of the following species does not exist?

1. ${\mathrm{Be}}_2^{+}$

2. Be₂

3. B₂

4. N₂

 

Which one of the following is not paramagnetic ?

1. NO

2. ${\mathrm{N}}_2^{+}$

3. CO

4. ${\mathrm{O}}_2^{-}$

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

1. 3

2. 2

3. 6

4. 4

Which of the following is not isostructural with SiCl₄? 

1. SCl₄     

2. SO₄^2-

^3. PO₄3-

4. NH₄⁺

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

Which of the following has  $\mathrm{p\pi } -\mathrm{d\pi }$ bonding?

1. ${\mathrm{NO}}_3^{-}$

2. ${\mathrm{SO}}_3^{2-}$

3. ${\mathrm{BO}}_3^{3-}$

4.${\mathrm{CO}}_3^{2-}$

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

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 which of the following lists rank the nitrogen species in terms of increasing 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. ${\mathrm{N}}_2^{-} < {\mathrm{N}}_2^{2-} < {\mathrm{N}}_2$

Among the following molecules/ions BF₃, NO₂^-, NH₂^- , and H₂O, the central atom is sp² hybridized in :  

1. NO₂^- and NH₂^-

2. NH₂^-  and H₂O

3. NO₂^- and H₂O

4. BF₃ and NO₂^-