How does the interaction of polar covalent bonds allow hydrogen bonds to form?
When hydrogen is bound to a ..........
When hydrogen is bound to a strongly electronegative element, i.e.
And thus a molecular dipole is generated, and in the bulk solution the dipoles line up to given an extra, potent intermolecular force that is known as
For hydrogen fluoride, we could represent this interaction as
And see this old answer.
And compare the boiling points of water, ammonia, and hydrogen fluoride with those of the lower group hydrides. The boiling points of these materials are absurdly high.