Hydrogen bonding Weak electrostatic force of attraction

1. Hydrogen
bonding
Prsented by,
Layba Saifi
M.Sc. Zoology
R.G. P.G.College Meerut

2. HYDROGEN BONDING

3. INTRODUCTION
The concept of hydrogen bonding
was first proposed in 1920 by
wendell latimer & worth rodebush .
They used the concept to explain
the anomalous properties of water,
such as its boiling point and freezing
point .

4. Wendell latimer worth rodebush

5. Definition
Hydrogen bonding is weak
electrostatic force of attraction
that occurs between a
hydrogen atom & an
electronegative atom ( flourine ,
oxygen & nitrogen).

6.  Usually a hydrogen bond is represented by
dotted lines ------------ .
Covalent bond is represented by solid line
 Hydrogen bond is weaker as compare to a
covalent bond.

7. • The H atom is more covalently
bonded to a more electronegative
atom, called the donor & is
attracted to another
electronegative atom with a lone
pair of electrons, called the
acceptor.

8. Condition for hydrogen bonding
• Hydrogen atom should be linked to
a highly electronegative atoms
such as f, o, n.
• The size of electronegative atom
should be small .

9. Types of h-bonding
Intermolecular H- Bonding
Intramolecular H- Bonding

10. Intermolecular h- bonding
• This type of bonding is formed between two
same or different molecules when combine
together to form a dimer or polymer respectively
& leads to a phenomenon called association.
• Intermolecular H – Bonding increase the boiling
points of the compound and also its solubility in
water.
• Intermolecular H-Bonding is stronger than
Intramolecular H-Bonding.

11. Intermolecular h-bonding

12. Intramolecular H-bonding
• This type of bonding occur when hydrogen bond is
formed within the two atoms of the same
molecule & leads to a phenomenon called
chelation.
• This type of hydrogen bond frequently occurs in
organic compound & result in the cyclisation ( six
or five member ring ) molecules.
• This type of H-bonding decreases the boiling point
of the compound & also its solubility in water.

13. Intramolecular h-bonding

14. Application of h-bonding
 Hydrogen bonding is responsible for the
structure of protein & nucleic acid , such as
DNA.
Hydrogen bonding is responsible for many of
water’s properties , including its high boiling
point & surface tension .
Hydrogen bonding allows water to stick to itself
(cohesion) and other molecules (adhesion).