Examples: Hydrogen

While hydrogen is the most abundant element in the universe, understanding it permits one to investigate a wide range of scientific phenomena. With this in mind, the CBSE has included this topic in their curriculum so that interested students can study the fundamentals of this element.

What is Hydrogen Bonding?

Hydrogen bonding develops hydrogen bonds produced by the collaboration of dipole-dipole between a hydrogen atom destined to a strongly electronegative atom and an extra electronegative atom. Hydrogen is covalently bound to the more electronegative oxygen atom in water molecules (H2O). Therefore, bonding occurs in water molecules due to dipole-dipole interactions between the hydrogen atom of one water molecule and the oxygen atom of another H2O molecule.

Only in molecules when hydrogen is covalently bound to one of three elements: fluorine, oxygen, or nitrogen, does hydrogen bonding occur. 

Types of Hydrogen Bonding

There are two types of bonds: 

Intermolecular Hydrogen Bonding

When hydrogen bonds develop between molecules of the same substance or even different, this is known as intermolecular bonding. Some intermolecular hydrogen bonding examples include water, ammonia, alcohol, etc.

Intramolecular Hydrogen Bonding

Hydrogen bonding that happens within a single molecule is called intramolecular hydrogen bonding. Some intramolecular hydrogen bonding examples include chemical bonds such as ionic, covalent, and metallic bonds.

A link is formed between the more electronegative atoms of one group and the hydrogen atoms of the other group.

What are the Conditions for Hydrogen Bonding?

When a hydrogen atom is connected to a highly electronegative atom in a molecule, it pulls the communal duo of electrons closer together, making one end slightly negative and the other somewhat positive. As a result, a weak bond is formed when the negative close of one molecule appeals to the positive end of the other. This form of bond is known as a hydrogen bond.

Due to hydrogen bonding, a hydrogen atom links the two electronegative atoms simultaneously, one via a covalent bond and the other via a hydrogen bond. The following are the hydrogen bonding criteria:

The hydrogen atom in the molecule must be paired with a strongly electronegative atom. A molecule’s polarization is proportional to its electronegativity.

Examples of Hydrogen Bonding

Here are the examples of hydrogen bonding that may help you understand the topic in a better manner;

Hydrogen Bonding in Hydrogen fluoride

The strongest hydrogen bond is formed by fluorine, which has the highest electronegativity.

Water Hydrogen Bonding

A highly electronegative oxygen atom is bonded to the hydrogen atom in a water molecule. As a result, the oxygen atom is more attracted to a collective couple of electrons. Therefore this end of the molecule becomes negative, while the hydrogen atoms become positive.

Hydrogen Bonding in Ammonia

This is another example of hydrogen that comprises nitrogen atoms that are strongly electronegative and are coupled to hydrogen atoms.

Hydrogen Bonding in Alcohols and Carboxylic acid

Alcohol is a chemical molecule with a -OH group attached to it. Hydrogen bonding is readily produced when any hydrogen atom molecule is directly coupled to either oxygen or nitrogen.

Hydrogen Bonding in Polymers

The importance of hydrogen bonding in establishing the 3D architectures and characteristics of synthetic and natural proteins cannot be overstated. Hydrogen bonds are also significant in the structure of cellulose and cellulose-derived polymers like cotton and flax.

Properties of Hydrogen Bonding

• Solubility: Because of the hydrogen bonding between water and the alcohol molecule, lower alcohols are soluble in water.

• Volatility: Compounds with hydrogen bonding between separate molecules have a higher boiling point and are less volatile.

• Viscosity and surface tension: Hydrogen bonding is found in compounds that have an associated molecule. As a result, their flow becomes more complicated. They have high surface tension and have a higher viscosity.

• The lower density of ice than water: In solid ice, hydrogen bonding causes water molecules to form a cage-like structure. Each water molecule is tetrahedrally connected to four other water molecules. 

The molecules are not as tightly packed as in the liquid form in the solid-state. This case-like structure collapses as ice melts, bringing the molecules closer together. As a result, the volume of water reduces while the density increases for the same quantity of water. As a result, at 273 K, ice has a lower density than water. 

Conclusion 

Given Hydrogen’s abundant nature, it has a wide range of scientific phenomena. Hydrogen bonding is amongst the most important properties that hydrogen exhibits – and its uses are observed in Water Hydrogen Bonding, Hydrogen Bonding in Polymers and in Alcohols and Carboxylic Acid allow for Hydrogen to be utilized effectively across multiple processes and activities.