Hydrogen Bonding and its Applications

Introduction

When a hydrogen bond and an atom with a lone pair attract each other and get bonded, such bonding is known as hydrogen bonding. Being a type of chemical bond, this type of bonding involves electrostatic forces of attraction. The hydrogen molecule must be bonded with a highly electronegative atom for this type of bonding. However, if there is one important thing to remember, it’s the fact that the hydrogen atoms don’t form a covalent bond, but the molecules that are involved during the reaction are covalent in nature. Let’s take an example to understand the fact- H2O molecule. When hydrogen is bonded to the most electronegative element, oxygen, it attracts the shared pairs of electrons towards itself. Thus, giving rise to the polar nature of the molecule. When such types of molecules are present in the bonding, one molecule attracts another molecule (both the ends should be opposite in charge). Want to dig deeper? Let’s understand more about hydrogen bonding and its applications.

What Is Hydrogen bonding? 

Hydrogen bonding is present between two atoms that are known to have high electronegativity differences. When positively charged hydrogen gets bonded with partially negatively charged atoms such as nitrogen or oxygen, the attractive force that develops between the atoms is known as hydrogen bonding. However, this type of bonding is weak as compared to the covalent bonding present in the atoms.

What is the reason behind the formation of hydrogen bonding? 

The reason behind the occurrence of hydrogen bonding is that there is the presence of a highly electronegative element in the bond. When hydrogen and a highly electronegative element get bonded with each other, it leads to the formation of polar charges. That is, the electronegative starts to pull the electrons towards itself. The unequal electron density across the molecule leads to the formation of dipole charges. After this, the partially positively charged hydrogen is attracted towards the partially negatively charged oxygen, resulting in the formation of hydrogen bonds. 

Types of hydrogen bonding

Depending on the atoms participating in the formation of molecules, different types of hydrogen bonding are recognised. Generally, there are two main types of hydrogen bonding – intermolecular hydrogen bonding and intramolecular hydrogen bonding. Let’s explain both types in detail.

• Intermolecular hydrogen bonding 

The hydrogen bonding developed between different molecules of the same or different compounds is known as intermolecular hydrogen bonding. During such a type of bonding, the compound should have an acceptor atom such as partially positively charged hydrogen along with a partially negatively charged atom or donor atom. When such a condition is satisfied, it leads to the formation of intermolecular hydrogen bonding. Some of the examples of this type of bonding are between aldehyde and water molecules or the type of bonding in ammonia, water, or alcohol.

• Intramolecular hydrogen bonding 

The hydrogen bonding that is known to develop within the same molecule is known as intramolecular hydrogen bonding. During this type of bonding, the hydrogen atom of one group attracts the highly electronegative atom present in another group. As this type of bonding occurs within the molecule, there is no need for any other atoms to participate. Let’s take an example to understand this type of bonding. The bonding present in the water molecule is known as intramolecular hydrogen bonding. The fact is that the bonding develops between partially positively charged hydrogen groups and partially negatively charged oxygen atoms. The imbalance in the charges present between the molecules gives rise to hydrogen bonding with polarity. 

 Another example of intramolecular hydrogen bonding is NH3 hydrogen bonding. During this type of hydrogen bonding, the nitrogen atom having a high electronegativity value will attract the electron pair towards itself. On the other hand, it results in the development of a positive charge around hydrogen. This electron shifting leads to the formation of hydrogen bonding in the NH3 or ammonia molecule. However, the bonding present in the molecule isn’t that strong, and that’s because nitrogen has only one lone pair. Thus, it can’t satisfy all hydrogen atoms. This is why water molecules have a greater boiling point as compared to ammonia.

Applications Of Hydrogen Bonding 

Many biological and chemical processes involve hydrogen bonding. Also, many natural phenomena occur due to hydrogen bonding. Here are a few applications of hydrogen bonding.

• Water has a specific property through which it can attract and stick to itself. This property is known as cohesion. And when the water molecules get attached to other molecules, this property is known as adhesion. When the water droplets fall on the leaf, the intramolecular hydrogen bonding present between water and hydrogen is less substantial as compared to the hydrogen bonds present between the water molecules. This property of water explains the high surface tension of water.

• The secondary, tertiary, and quaternary proteins and nucleic acids’ structures are formed due to the presence of intramolecular hydrogen bonding. This type of bonding is known to maintain the shape and structures of these acids and proteins.

• The double-helix model of DNA (deoxyribonucleic acid) consists of two intertwined strands held together by a base pair. The hydrogen bonds between the bases on adjacent strands are responsible for this

Properties Of Hydrogen Bonding 

Here are the properties of hydrogen bonding that make it different from others. 

• The molecules present in the type of bonding have a weak force of attraction. 

• It can easily alter the physical properties of the molecule. This type of bonding is known to enhance the boiling and melting point of the substance. 

• The hydrogen bonds are stronger than Van der Waals but are weaker than the covalent and ionic bonds. 

• The solubility of the molecules in any substance is recognised by hydrogen bonding.

• Surface tension, as well as the high viscosity of the substance, is determined by hydrogen bonding.

Conclusion

Hydrogen bonding and its applications are an important topic in chemistry. This type of bonding is known to explain different phenomena in the compounds. The two types of hydrogen bonding- intermolecular hydrogen bonding and intramolecular hydrogen bonding explain the type of molecule involved in a particular compound. Due to the presence of intramolecular hydrogen bonding, the nonpolar molecules have a lower boiling point as compared to the polar molecules. Water and organic compounds with hydrogen bonding are known to possess little solubility. We hope this article will help you to know more about hydrogen bonding and its applications.