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

1. BeF₂

2. BF₃

3. C₂H₂

4. NH₃