Question

The decreasing order of the boiling points of the following hydrides is:
i) $N{H_3}$ii) $P{H_3}$ iii) $As{H_3}$ Iv) $Sb{H_3}$ v) ${H_2}O$
A) $\left( v \right) > \left( {iv} \right) > \left( i \right) > \left( {iii} \right) > \left( {ii} \right)$
B) $\left( v \right) > \left( i \right) > \left( {ii} \right) > \left( {iii} \right) > \left( {iv} \right)$
C) $\left( {ii} \right) > \left( {iv} \right) > \left( {iii} \right) > \left( i \right) > \left( v \right)$
D) $\left( {iv} \right) > \left( {iii} \right) > \left( i \right) > \left( {ii} \right) > \left( v \right)$

Answer 1

Hydrides are the family of compounds that contains a metal or metalloid with the combination of hydrogen atoms. The boiling point of hydrides increases along with the increase in boiling point. The intermolecular hydrogen bonding affects the boiling point of hydrides.

Complete answer:
Periodic table consists of chemical elements arranged in the increasing order of atomic numbers. These elements are arranged in the vertical columns and horizontal rows. The vertical columns were known as groups and the horizontal rows were known as periods. The elements nitrogen, phosphorus, arsenic, antimony (stibium) and bismuth belong to group $15$ . These all-elements form hydrides with the combination of hydrogen atoms. The boiling point of hydrides increases along with the increase in atomic number.
Thus, the order of above hydrides will be $Sb{H_3} > As{H_3} > P{H_3} > N{H_3}$
But as the nitrogen is more electronegative and involved in hydrogen binding the ammonia has more boiling point compared to the arsenic hydride and phosphorus hydride.
The oxygen is more electronegative compared to nitrogen. Thus, water has more boiling point due to the presence of hydrogen bonding.
The decreasing order of the boiling points of the given hydrides are in the order of:
${H_2}O > Sb{H_3} > N{H_3} > As{H_3} > P{H_3}$

Option A is the correct one.

Note:
When the least electronegative atom is placed between the two atoms with high electronegative atoms, it is involved in the hydrogen bonding. Oxygen is more electronegative than nitrogen resulting in the high boiling point of water compared to ammonia and other hydrides.