Question

Of the following hydrides which one has the lowest boiling point?
A \[\text{As}{{\text{H}}_{\text{3}}}\] ​
B \[\text{Sb}{{\text{H}}_{\text{3}}}\]​
C \[\text{P}{{\text{H}}_{\text{3}}}\]​
D \[\text{N}{{\text{H}}_{\text{3}}}\]

Answer 1

Hint: Hydrides are compounds of binary hydrogens. The hydride can have basic, acidic, and neutral nature. Most of the elements present in the periodic table form hydrides. Hydrides of Highly electronegative elements show H-Bondings.

Complete step-by-step answer: With the exception of noble gases, many elements and the hydrogen molecule typically react to generate hydrides. The type of intermolecular force between the elements, their molecular weights, temperature, and other factors may all affect the characteristics, though.

Atomic radii get bigger in group 15 as you go from top to bottom. The size of hydrides similarly grows with increasing atomic radii. The magnitude of van der Waals forces increases along with size. The boiling point rises as van der Waals forces grow. Therefore, the boiling temperatures of its hydrides will rise as you descend group 15. This pattern predicts that among the group 15 hydrides, ammonia will have the lowest boiling point.

Ammonia, on the other hand, has a greater boiling point than phosphine. This is because ammonia molecules interact with one another through intermolecular hydrogen bonds. Phosphine molecules do not contain these connections.
Molecular association and a rise in the boiling point are caused by intermolecular hydrogen bonding. Therefore, phosphine has the lowest boiling point among the group 15 hydrides.

Option ‘C’ is correct

Note: Hydride of group 15 uses
-In a variety of chemical industries, they serve as reducing agents.
-They serve as powerful bases in the synthesis of organic compounds.
-Ammonia is also used as a non aqueous solvent for metals.