Question

Lapan we Uuwing Wiu reasons! i) In the hydrogen bonded structure of HF, which is the stronger bond:the shorter covalent bond or the longer hydrogen bond between different molecules?
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Answer 1

Answer:

In a molecule of water, there are two hydrogen bond donors, while a hydrogen fluoride molecule only has one donor. There is only one donor in HF, but there are 2 hydrogen atoms in H

2

O. The oxygen molecule in water has two lone pairs which are capable of accepting two hydrogen bonds. Therefore, a single water molecule can have up to 4 hydrogen bonds, i.e., 1 for each hydrogen and 2 for the oxygen. On the other hand, HF can only undergo 2 hydrogen bonds per molecule.

Hence, it is clear that water has more hydrogen bonds per molecule and per molecular mass as compared to HF which allows water to form a complex network of hydrogen bonding that creates a high surface tension and consequently a higher boiling point than HF.