Question
Define hydrogen bond. Is it weaker or stronger than the van der Waals forces?
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Answer
A hydrogen bond is defined as an attractive force acting between the hydrogen attached to an electronegative atom of one molecule and an electronegative atom of a different molecule (may be of the same kind).
Due to a difference between electronegativities, the bond pair between hydrogen and the electronegative atom gets drifted far away from the hydrogen atom. As a result, a hydrogen atom becomes electropositive with respect to the other atom and acquires a positive charge. a positive charge.
$4^\delta-\text{X}^{\delta-}.......\text{H}^{\delta+}-\text{X}^{\delta-}.......\text{H}^{\delta+}-\text{X}^\delta$
The magnitude of H-bonding is maximum in the solid state and minimum in the gaseous state.
There are two types of H-bonds:
- Intermolecular H-bond e.g., $\mathrm{HF}, \mathrm{H}_2 \mathrm{O}$ etc.
- Intramolecular H-bond e.g., o-nitrophenol.
- Hydrogen bonds are stronger than Van der Walls forces since hydrogen bonds are regarded as an extreme form of dipole-dipole interaction.
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$
\begin{aligned}
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\begin{aligned}
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