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. ${\mathrm{SO}}_2, {\mathrm{CO}}_2$

The correct order of the increasing bond angles in the following triatomic species is :  

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

AsF₅ molecule is trigonal bipyramidal. The hybrid orbitals used by As-atoms for bonding are

1. $d_{x^2-y^2}, d_{z^2}, s, p_x, p_y$

2. $d_{xy}, s,p_x, p_y, p_z$

3. $s, p_x, p_y, p_z, d_{xy}$

4. $d_{z^2}, s, p_x, p_y, p_z$

The types of hybrid orbitals of nitrogen in NO₂⁺, NO₃^- and NH₄⁺ respectively are expected to be

1. sp, sp³ and sp²

2. sp, sp² and sp³

3. sp², sp and sp³

4. sp², sp³ and sp

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  

Which of the following compounds does not exhibit hydrogen bonding?

1.	CH3CH2OH	2.
3.		4.

PCl₅ is highly unstable and in a solid-state, it exists as into  [PCl₄]⁺ and [PCl₆]^- ions.

The geometry of [PCl₆]^- is   

1. Octahedral

2. Tetrahedral

3. Square pyramidal

4. Square planar