What is hydrogen bond? How is it formed?
A hydrogen bond can be defined as the attractive force which binds hydrogen atom of one molecule with the electronegative atom (F, O or N).
Cause of formation of Hydrogen Bond:
When hydrogen is bonded to strongly electronegative element X, the electrons pair shared between the two atoms moves far away from a hydrogen atom. As a result, the hydrogen atoms becomes highly electropositive with respect to the other atom ‘X’. Since there is displacement of electrons towards X, the hydrogen acquires fractional positive charge (δ+) while X attain fractional negative charge (δ–). This result in the formation of a polar molecule having electrostatic force of attraction which can be represented as:
This weak electrostatic attraction constitutes hydrogen bond. For example,
