The state of hybridisation of 'B' atoms in borax $\left({\mathrm{Na}}_2{\mathrm{B}}_4{\mathrm{O}}_7<mspace\; width="1em"></mspace>·<mspace\; width="1em"></mspace>10{\mathrm{H}}_2\mathrm{O}\right)$ is

1.  All sp² hybridised

2.  Three sp² and one sp³ hybridised

3.  One sp² and three sp³ hybridised

4.  Two sp² and two sp³ hybridised

The total number of $\mathrm{\pi }$-bond electrons in the following structure is

1.  4

2.  8

3.  12

4.  16

Carbon suboxide $\left({\mathrm{C}}_3{\mathrm{O}}_2\right)$ has

1.  Linear structure

2.  Bent structure

3.  Trigonal structure

4.  Distorted tetrahedral structure

Which of the following gas is least polarizable?

1.  He

2.  Ne

3.  Kr

4.  Xe

Which of the following is correct order of dipole moment of the following?

1.  I  > II > III

2.  I = II = III

3.  III > II > I

4.  I > III > II

For the ${\mathrm{PO}}_4^{3-}$ ion, what are the formal charges on each oxygen atom and the bond order of the P-O bond, respectively?

The number of $\mathrm{P}-\mathrm{O}-\mathrm{P}$ linkages in ${\mathrm{P}}_4{\mathrm{O}}_{10}$ and ${\mathrm{P}}_4{\mathrm{O}}_6$ are respectively -

1.  6,6 

2.  6, 8

3.  8, 6

4.  8, 8

In which of the following molecule the intramolecular hydrogen bonding is not existing.

1.  chloral hydrate

2.  0-chlorophenol

3.  choral

4.  salicylic acid

Isostructural pair among the following is:

1. ${\mathrm{BCl}}_3$ $\mathrm{and}$ ${\mathrm{BrCl}}_3$

2. ${\mathrm{NH}}_3$ $\mathrm{and}$ ${\mathrm{NO}}_3^{-}$

3. ${\mathrm{NF}}_3$ $\mathrm{and}$ ${\mathrm{BF}}_3$

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

The correct order of covalent bond character among
LiCl, BeCl₂, BCl₃ and CCl₄, is:

1. LiCl < BeCl₂ > BCl₃ > CCl₄

2. LiCl > BeCl₂ < BCl₃ < CCl₄

3. LiCl < BeCl₂ < BCl₃ < CCl₄

4. LiCl > BeCl₂ > BCl₃ > CCl₄