Which one of the following is not paramagnetic ?

1. NO

2. ${\mathrm{N}}_2^{+}$

3. CO

4. ${\mathrm{O}}_2^{-}$

The angular shape of ozone molecule (O₃) consists of 

1. 1 sigma and 2 pi-bonds

2. 2 sigma and 2 pi-bonds

3. 1 sigma and 1 pi-bonds

4. 2 sigma and 1 pi-bonds

In which of the following molecules are all the bonds not equal?

1. ClF₃

2. BF₃

3.  PF₃

4. NF₃

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

Which one of the following is planar ?

1. XeF₄

2. XeO₄

3. XeO₃

4. XeO₃F₂

The dielectric constant of H₂O is 80. The electrostatic force of attraction between Na⁺ and Cl^- will be

1. reduced to $\frac{1}{40}$ in water than in air

2. reduced to $\frac{1}{80}$ in water than in air

3. will be increased to 80 in water than in air

4. will remain unchanged

Which of the following is isoelectronic? 

1. ${\mathrm{CO}}_2, {\mathrm{NO}}_2$

2. ${\mathrm{NO}}_2^{-}, {\mathrm{CO}}_2$

3. ${\mathrm{CN}}^{-}, \mathrm{CO}$

4. ${\mathrm{SO}}_2, {\mathrm{CO}}_2$

In an octahedral structure, the pair of d orbitals involved in d²sp³-hybridisation is:

1. $d_{x^2-y^2}, d_{z^2}$

2. $d_{xy}, d_{x^2\mathit{-}{y}^{\mathit{2}}}$

3. $d_{{\mathrm{z}}^2}, d_{xz}$

4. $d_{xy}, d_{yz}$

Equilateral shape has

1. sp hybridisation

2. sp² hybridisation

3. sp³ hybridisation

4. dsp² hybridisation

Which of the following statement is not correct from the view point of molecular orbital theory ?

1. Be₂ is not a stable molecule

2. He₂ is not a stable but He_2⁺ is expected to exist.

3. Bond strength of N₂ is maximum amongst the homonuclear diatomic molecules belonging to the second period.

4. The order of energies of molecular orbitals in N₂ molecule is

 s2s < s*2s < s2p_z < (p2p_x=p2p_y) < (p*2p_x=p*2p_y) < s*2p_z