Question

Although hydrogen has the smallest molar mass, helium has the lowest boiling point.Why?

Answer 1

It does? Well we will have to quote some data....

Explanation:

The normal boiling point of dihydrogen is `-252.9` `""^@C`.

That of helium is `-272.0` `""^@C`.

Now helium has a closed shell configuration, and is a hard atomic sphere. On the other hand, dihydrogen has 2 electrons shared between two atoms, and this electron cloud can be polarized, and deformed, and the polarizability of the electron cloud gives rise to to a degree of intermolecular interaction....i.e. between molecules, NOT between atoms.....

And since intermolecular force is greater for dihydrogen, this is expressed in the observed boiling point.