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 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  

PCl₅ is highly unstable and in 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

Which of the following species has maximum number of lone-pair of electrons on the central atom ?

(1) XeF₂

(2) H₃O⁺

(3) XeF₄

(4) XeF₆

The number of sigma bonds in P₄O₁₀ is 

(1) 6

(2) 16

(3) 20

(4) 7

A s bonded molecule MX₃ is T-shaped. The number of non-bonding pairs of electrons is :

(1) 0

(2) 2

(3) 1

(4) Can be predicted only if atomic number of M is known,

In a chemical change from ${\mathrm{PCl}}_3 \stackrel{ }{\to }{\mathrm{PCl}}_5$ the hybrid state of P changes from:

(1) sp² to sp³

(2) sp³ to sp²

(3) sp³ to sp³d

(4) sp³ to dsp

In which case observed dipole moment is greater than theoretical dipole moment?

1.

2.

3.

4.

Amongst ${\mathrm{H}}_2\mathrm{O}, {\mathrm{H}}_2\mathrm{S}, {\mathrm{H}}_2\mathrm{Se} \mathrm{and} {\mathrm{H}}_2\mathrm{Te}$ the one with the highest boiling point is:

1. H₂O because of H-bonding.

2. H₂Te because of higher molecular weight.

3. H₂S because of H-bonding.

4. H₂Se because of lower molecular weight.

Which of the following species contains an equal number of $\mathrm{\sigma }$ and $\mathrm{\pi }$ bonds?

(a) ${\mathrm{HCO}}_3^{-}$                                    (b) XeO₄

(c) (CN)₂                                      (d) CH₂(CN)₂