Explain different types of hydrogen bonds with examples.

Explanation

The concept of H - bond is due to Huggins, Latimer and Rodebush.
Def : "The electrostatic force of attraction between a partially charged hydrogen atom of a molecule and a highly electronegative atom of the same molecule or different molecule is known as H-bond."
Explanation :
1) The molecule having H-bonds should have a highly electronegative atom like F,O or N directly linked to H-atom by a covalent bond.
2) H - bond is stronger than van der Waal's forces but weaker than ionic and covalent bonds.
van der waal's forces `lt` H - bond
Energy : 2 - 10 kJ `mol^(-1) " " 2-40 kJ mol^(-1)`
`" "lt` Covalent bond `lt` Ionic bond
`" "` 200-400 kJ `mol^(-1)`
3) The strength of H - bond increases with the EN of the atom attached covalently to H atom.
Types of H - bonds : 2 types. 1) Intramolecular H - bonding and 2) Inter-molecular H - bonding
1) Intramolecular H - bonding : The H - bonding formed between H atom of a molecule and a highly electronegative atom of the same molecule, is called intramolecular hydrogen bond.
Ex :

2) Inter-molecular H - bonding : The H - bonding formed in between H - atom of one molecule and a highly electronegative atom of another molecule of same substance or different substances is called intermolecular hydrogen bond.
Ex :
`----*H^(+delta)"_______"underset(H^(+delta))underset("\")(O^(-2delta))----*underset(H^(+delta))underset("\")(H^(+delta))"____"O^(-2delta)----*underset(H^(+delta))underset("\")(H^(+delta))---*O^(-2delta)--`
H - bonding in water molecules
Consequences of H - bonding :
1) Highly viscous nature of `H_(2)SO_(4), HNO_(3), H_(3)PO_(4)` etc, is due to H - bonding.
2) The high b.p. of water is due to H - bonds in it.
3) `H_(2)O` is a liquid but `H_(2)S` is a gas, since H - bond is present in `H_(2)O` only.