Which among the following does not contain a set of isoelectronic species?

1. $\mathrm{S}{{\mathrm{O}}_3}^{2-\mathrm{}}$, CO₃^2-,NO₃^-

2. ${\mathrm{CN}}^{-},<mspace\; width="1em"></mspace>{\mathrm{N}}_2,<mspace\; width="1em"></mspace>\mathrm{CO}$

3. ${\mathrm{BO}}_3^{3-}<mspace\; width="1em"></mspace>,<mspace\; width="1em"></mspace>{\mathrm{CO}}_3^{2-<mspace\; width="1em"></mspace>},\mathrm{N}{{\mathrm{O}}_3}^{-}$

4. ${\mathrm{PO}}_4^{3-},<mspace\; width="1em"></mspace>{\mathrm{SO}}_4^{2-},<mspace\; width="1em"></mspace>\mathrm{Cl}{{\mathrm{O}}_4}^{-}$

A molecule or ion that has an unequal bond length is:

The correct increasing order of the polarizing power of the cationic species  ${\mathrm{K}}^{+},<mspace\; width="1em"></mspace>{\mathrm{Ca}}^{2+},<mspace\; width="1em"></mspace>{\mathrm{Mg}}^{2+},<mspace\; width="1em"></mspace>{\mathrm{Be}}^{2+}$is: 

1. ${\mathrm{Be}}^{2+}<{\mathrm{K}}^{+}<{\mathrm{Ca}}^{2+}<{\mathrm{Mg}}^{2+}$

2. ${\mathrm{K}}^{+}<{\mathrm{Ca}}^{2+}<{\mathrm{Mg}}^{2+}<{\mathrm{Be}}^{2+}$

3. ${\mathrm{Ca}}^{2+}<{\mathrm{Mg}}^{2+}<{\mathrm{Be}}^{2+}<{\mathrm{K}}^{+}$

4. ${\mathrm{Mg}}^{2+}<{\mathrm{Be}}^{2+}<{\mathrm{K}}^{+}<{\mathrm{Ca}}^{2+}$

The specie with the shortest bond length is:

Among the following, the maximum covalent character is shown by which compound:

1. ${\mathrm{MgCl}}_2$

2.$$ ${\mathrm{FeCl}}_2$

3. ${\mathrm{AlCl}}_3$

4. ${\mathrm{SnCl}}_2$

From the following pairs, the two species that are not isostructural are : 

The number of sigma ($\mathrm{\sigma }$) and pi ($\mathrm{\pi }$) bonds in pent-2-en-4-yne is:

1.  13 $\mathrm{\sigma }$ bonds and no $\mathrm{\pi }$ bond.

2.  10 $\mathrm{\sigma }$ bonds and 3 $\mathrm{\pi }$ bonds.

3.  8 $\mathrm{\sigma }$ bonds and 5 $\mathrm{\pi }$ bonds.

4.  11 $\mathrm{\sigma }$ bonds and 2 $\mathrm{\pi }$ bonds.

Match the compounds of Xe in column I with the molecular structure in column II.

The correct relationship for the bond angle of water and dimethyl ether $\left({\mathrm{CH}}_3-\underset{..}{\overset{..}{\mathrm{O}}}-{\mathrm{CH}}_3\right)$ is: 

The decreasing order of ionic character of the N-H, F-H, C-H, and O-H, is :