Paramagnetic species among the following is:

1. CO               

2. ${\mathrm{O}}_2^{-}$

3. CN^-               

4. NO⁺

The correct order of solubility in an aqueous medium is: 

1. CuS > ZnS > Na₂S

2. ZnS > Na₂S > CuS

3. Na₂S > CuS > ZnS

4. Na₂S > ZnS > CuS

XeF₂ is isostructural with : 

1. TeF₂

2. ICI₂^-

3. SbCl₃

4. BCl₃

Which one of the following molecules contain no $\mathrm{\pi }$ -bond?

1. CO₂

2. H₂O

3. SO₂

4. NO₂

Which one of he following pairs is isostructural (i.e., having the same shape and

hybridization)?

1. [BCl₃ and BrCl₃]

2. [NH₃ and ${\mathrm{NO}}_3^{-}$]

3. [NF₃ and BF₃]

4. [${\mathrm{BF}}_4^{-}$ and ${\mathrm{NH}}_4^{+}$]

Considering the state of hybridisation of carbon atoms, find out the molecule among the

following which is linear.

1. HC≡CH

2. CH₂ = CH—CH₂—C = CH

3. CH₃ — CH₂ — CH₂ — CH₃

4. CH₃—CH = CH—CH₃

The correct order of increasing bond length of 

C-H, C-O, C-C and C=C is:

1. C-C<C=C<C-O<C-H

2. C-O<C-H<C-C<C=C

3. C-H<C-O<C-C<C=C

4. C-H<C=C<C-O<C-C

Which of the following compounds has the lowest melting point?

1. CaBr₂

2. CaI₂

3. CaF₂

4. CaCl₂

Identify the species having the shortest O–O bond length:

1.  O₂
2.  O₂⁻
3.  O₂²⁻ 
4.  O₂⁺

In which of the following pairs of molecules/ions, the central atoms have \(\mathrm{sp}^2\) hybridisation?