Which of the following would have a permanent dipole moment ?

1. BF₃

2. SiF₄

3. SF₄

4. XeF₄

In the case of alkali metals, the covalent character decreases in the order

1. MCl > MI > MBr > MF

2. MF > MCl >  MBr > MI 

3. MF > MCl > MI > MBr

4. MI > MBr > MCl > MF

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

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: