What is the decreasing order of boiling points of the \[{\rm{V}}\] group of hydrides?
A.\[N{H_3} > P{H_3} > As{H_3} > Sb{H_3}\]
B.\[Sb{H_3} > As{H_3} > P{H_3} > N{H_3}\]
C.\[P{H_3} > N{H_3} > As{H_3} > Sb{H_3}\]
D.\[Sb{H_3} > N{H_3} > As{H_3} > P{H_3}\]
Last updated date: 26th Mar 2023
•
Total views: 207.6k
•
Views today: 1.84k
Answer
207.6k+ views
Hint: Group \[{\rm{V}}\] in the periodic table is known as the nitrogen family and main elements of this group are nitrogen, phosphorus, arsenic, antimony and bismuth. As there are three electrons present in the valence subshell of each element therefore the elements of the nitrogen family form hydrides of types \[A{H_3}\].
Complete answer:
As we know, on moving down the group the atomic size of the elements increases therefore the Vander Waal forces acting between the atoms also increases which leads to increase in the bond strength of molecules. As the bond strength of a molecule increases, the molecule will require more heat to break its bonds. Therefore, the boiling points of hydrides \[{\rm{V}}\] group increases down the group.
The boiling point of ammonia is exceptionally higher than the boiling points of hydrides of arsenic and phosphorus because of hydrogen bonding that exists between the atoms of nitrogen and hydrogen.
Therefore, the correct decreasing order of boiling points of \[{\rm{V}}\] group of hydrides is \[Sb{H_3} > N{H_3} > As{H_3} > P{H_3}\]
So, option (D) is the correct answer.
Note:
Hydrogen bonding: It is a special type of dipole-dipole interactions between the highly electronegative elements (fluorine, oxygen and nitrogen) and the hydrogen atom via covalent bonding. There are two types of hydrogen bonding:
Intermolecular hydrogen bonding- These are the interactions between the atoms of one molecule with the atoms of another molecule. Example: hydrogen fluoride, water, etc.
Intramolecular hydrogen bonding- These are the interactions between two atoms within the same molecule. Example: ethylene glycol.
Complete answer:
As we know, on moving down the group the atomic size of the elements increases therefore the Vander Waal forces acting between the atoms also increases which leads to increase in the bond strength of molecules. As the bond strength of a molecule increases, the molecule will require more heat to break its bonds. Therefore, the boiling points of hydrides \[{\rm{V}}\] group increases down the group.
The boiling point of ammonia is exceptionally higher than the boiling points of hydrides of arsenic and phosphorus because of hydrogen bonding that exists between the atoms of nitrogen and hydrogen.
Therefore, the correct decreasing order of boiling points of \[{\rm{V}}\] group of hydrides is \[Sb{H_3} > N{H_3} > As{H_3} > P{H_3}\]
So, option (D) is the correct answer.
Note:
Hydrogen bonding: It is a special type of dipole-dipole interactions between the highly electronegative elements (fluorine, oxygen and nitrogen) and the hydrogen atom via covalent bonding. There are two types of hydrogen bonding:
Intermolecular hydrogen bonding- These are the interactions between the atoms of one molecule with the atoms of another molecule. Example: hydrogen fluoride, water, etc.
Intramolecular hydrogen bonding- These are the interactions between two atoms within the same molecule. Example: ethylene glycol.
Recently Updated Pages
In India on the occasion of marriages the fireworks class 12 chemistry JEE_Main

The alkaline earth metals Ba Sr Ca and Mg may be arranged class 12 chemistry JEE_Main

Which of the following has the highest electrode potential class 12 chemistry JEE_Main

Which of the following is a true peroxide A rmSrmOrm2 class 12 chemistry JEE_Main

Which element possesses the biggest atomic radii A class 11 chemistry JEE_Main

Phosphine is obtained from the following ore A Calcium class 12 chemistry JEE_Main
