What is the correct order of the boiling points of \(\mathrm{H}_2 \mathrm{O}, \mathrm{HF}, \text{ and} \ \mathrm{NH}_3\) ?

1. HF > H₂O > NH₃

2. H₂O > HF > NH₃

3. NH₃ > HF > H₂O

4. NH₃ > H₂O > HF

In ${\mathrm{PO}}_4^{3-}$ ion, the formal charge on the oxygen atom of the P-O bond is :

Which species lacks tetrahedral geometry?

The number of $\mathrm{\pi }$ bonds and $\mathrm{\sigma }$ bonds in the following structure is :

The species that does not have unpaired electrons is:
 

If the electronic configuration of an element is $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^{6}3{\mathrm{d}}^{2}4{\mathrm{s}}^2$, the four electrons that participate in the chemical bond formation will be from :

The correct bond angle for \(\mathrm{sp}^2\) hybridization is:
1. \(90^\circ\)
2. \(120^\circ\)
3. \(180^\circ\)
4. \(109^\circ\)

The electronic configurations of the elements A, B, and C are given below.

$\mathrm{A}<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>1{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{p}}^6$
$\mathrm{B}<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>1{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{p}}^6<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{p}}^3$
$\mathrm{C}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>1{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{p}}^6<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{p}}^5$

The stable form of A may be represented by the formula:

The electronic configurations of the elements A, B, and C are given below.

$\mathrm{A}<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>1{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{p}}^6$
$\mathrm{B}<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>1{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{p}}^6<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{p}}^3$
$\mathrm{C}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>1{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{p}}^6<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{p}}^5$

The stable form of C may be represented by the formula : 

The electronic configurations of the elements A, B, and C are given below.

$\mathrm{A}<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>1{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{p}}^6$
$\mathrm{B}<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>1{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{p}}^6<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{p}}^3$
$\mathrm{C}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>1{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>2{\mathrm{p}}^6<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{s}}^2<mspace\; width="1em"></mspace><mspace\; width="1em"></mspace>3{\mathrm{p}}^5$

The bond between B and C will be :