Structure, Preparation, Reactions and Uses of Hydrogen

INTRODUCTION

Hydrogen is the most abundant element in the universe, and its name derives from the Greek words hydro, which means water, and genes, which means formation. It can be found in its simplest molecular form, dihydrogen. It accounts for approximately 70% of the total mass of the universe. The sun is the most important element in the solar system. Major components of the large planets such as Jupiter and Saturn are hydrogen and helium. In its combined form, it accounts for 15.4 percent of the earth’s crust and oceans, according to the United Nations.

Preparation of Dihydrogen

The following procedures can be used to make dihydrogen. –

1)Dihydrogen preparation methods in the laboratory

2)Commercially available methods of preparing dihydrogen

Methods for preparing dihydrogen in the laboratory – During the production of dihydrogen, the following two methods are employed:

• When granulated zinc is reacting with dilute hydrochloric acid, the result is dihydrogen, which can be prepared in laboratories by reacting granulated zinc with dilute HCl. The following is an illustration of a reaction:

Zn + 2H+ → Zn2+ + H2

• In laboratories, the reaction of zinc with aqueous alkali can also be used to produce dihydrogen, which is produced by the reaction of zinc with aqueous alkali. As a result of the reaction, sodium zincate is produced as a byproduct. The following is an illustration of a reaction:

Zn + 2NaOH → Na2ZnO2 + H2

Commercial methods for the production of dihydrogen – The following are some of the most commonly used methods for commercial production of dihydrogen:

• The electrolysis of acidified water with platinum electrodes results in the production of hydrogen. The following is an illustration of a reaction:

  2H2O → 2H2 + O2  

• It can be made by electrolyzing an aqueous barium hydroxide solution with nickel electrodes, which is a process known as electrolysis. As a result, the dihydrogen that has been obtained is extremely pure in nature.
• When sodium hydroxide and chlorine are combined to make a chemical reaction, dihydrogen is produced as a byproduct of the process.
• It can also be produced by the high-temperature reaction of steam with hydrocarbons or coke in the presence of a catalyst in the absence of a catalyst. The following are illustrations of reactions:

CnH2n+2 + nH2O  1270K,Ni → nCO + (2n+1)H2

Dihydrogen’s Physical and Chemical Characteristics

The following are the physical characteristics of dihydrogen:

• It is colourless, tasteless, and odourless .
• It is completely insoluble in water.
• It has a high combustible index.
• It is significantly lighter than air.
• It has a melting point of 13.96 degrees Celsius.
• Its boiling point is 20.39 degrees Celsius.
• It has a density of 0.09 grammes per litre.
• The enthalpy of fusion for this substance is 0.117 kJ/mol.

The chemical properties of dihydrogen

Dihydrogen is a relatively stable gas that only dissociates into hydrogen atoms when heated above 2000 degrees Celsius, H2→H + H. The bond dissociation energy of this compound is extremely high. For dihydrogen, the enthalpy is 435.9kJ/mol. It is not very reactive due to the high bond dissociation energy it possesses. It does, however, combine with a wide variety of elements and compounds. There are the following reactions depicted. –

Reaction with Metals – It reacts with metals and forms hydrides that are similar to the metals. To give an example, when it reacts with sodium, it produces sodium hydride. The following is an illustration of a reaction:

2Na + H2→2NaH is a chemical formula.

In addition, it reacts with non-metals, resulting in the formation of the corresponding products. A few illustrations of its reactions with various non-metals are listed below —

2H2 + O2 → 2H2O

N2 + 3H2→2NH3

H2 + Cl2→2HCl 

When it comes into contact with unsaturated hydrocarbons such as ethylene and acetylene, it produces saturated hydrocarbons as a result of the reaction. The following is an illustration of a reaction:

H2C=CH2 + H2  Ni, 473K →  CH3-CH3

HCCH + 2H2  Ni, 473K →  CH3-CH3

Uses of Dihydrogen

• It is employed as a dehydrating agent.

Hydrogenation of vegetable oils is accomplished through the use of this chemical.

• In the form of liquid hydrogen, it is used as a propellant for rockets.
• In the production of synthetic gasoline, it is used as a catalyst.
• In Haber’s process of ammonia preparation, it is used as a catalyst.
• In the preparation of HCl, it is used as a solvent. 
• In the production of metal hydrides, it is used as a catalyst.

It is used in the production of vanaspati fats, among other things.

• Heavily metallurgical processes, such as those involving heavy metals, call for the use of this chemical.

Hydrogen Peroxide

It is a chemical compound composed of hydrogen and oxygen that is primarily used in the treatment of domestic and industrial effluents for pollution control purposes. The French chemist Thenard was the one who discovered it.

Preparation of hydrogen peroxide – 

The following methods can be used to make hydrogen peroxide:

The production of hydrogen peroxide is achieved by acidifying barium peroxide and removing excess water by evaporation under reduced pressure. The following is an illustration of a reaction:

BaO2.8H20+H2SO4→BaSO4+H2O2+8H20.

Characteristics of Hydrogen Peroxide 

Physical properties.

• It is Colorless
• It has no discernible odour.
• It dissolves completely in water.
• Hydrogen peroxide in its purest form is a pale blue syrupy liquid.
• If kept at –0.5°C, it freezes and has a density of 1.4 when kept in its purest form.
• The diamagnetic property of hydrogen peroxide is well known.
• In comparison to water, it has a stronger association with hydrogen bonding.
• Despite the fact that it is a better polar solvent than water. However, because of its high autooxidation potential, it cannot be used as a food additive.
• The dipole moment of hydrogen peroxide is 2.1 D.

Chemical Characteristics

It has the ability to act as both an oxidising and a reducing agent in both acidic and alkaline media.

Iron(SO4)3 is formed by combining 2FeSO4 with H2SO4 and H2O2 to form Iron(SO4)3 + 2H20 (in acidic medium as oxidising agent)

Pure hydrogen peroxide is an unstable liquid that decomposes into water and oxygen either at room temperature or when heated to a high temperature. The following is an illustration of a reaction:

2H2O2→2H2O + O2 ∆H = -196 kilocalories

Uses of Hydrogen Peroxide

A few of the applications for hydrogen peroxide are listed below:

• Because of the release of nascent oxygen, it has the effect of bleaching the water.
• It is used to bleach delicate materials such as silk, wool, leather, and other similar materials.
• It is also employed as a hair bleaching agent.
• Numerous chemicals, such as sodium perborate and percarbonate, among others, are produced using this substance.
• It is used in the production of hydroquinone, tartaric acid, and other chemicals.
• It is employed in environmental chemistry, for example, in the treatment of domestic and industrial effluents for pollution control purposes.

CONCLUSION

Hydrogen is a chemical element with the symbol H and the atomic number 1 in the periodic table. Hydrogen is the lightest element in the periodic table.The following procedures can be used to make dihydrogen.(1)Dihydrogen preparation methods in the laboratory(2)Commercially available methods of preparing dihydrogen.It is colourless, tasteless, and odourless .It is completely insoluble in water.It has a high combustible index.Hydrogen Peroxide  is a chemical compound composed of hydrogen and oxygen that is primarily used in the treatment of domestic and industrial effluents for pollution control purposes.It is Colorless It has no discernible odour.It dissolves completely in water.Hydrogen peroxide is used to bleach delicate materials such as silk, wool, leather, and other similar materials.