Dihydrogen is the more common name for hydrogen, which is a substance becoming the most basic of all chemical elements. Numerous applications are going to the most diverse fields of sciences and industries. It fuels rockets other than in the periodic table to send people living into orbit and on the other side of the ground, it more and more fuels clean energies. Versatility and important position in parameters regarding industry and environmental control underline the ways for its production through steam reforming of natural gas and electrolysis of water.
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The article will encompass all matters about him, from his production methods to his physical and chemical properties. We elaborate diatomic nature of hydrogen gas under normal conditions with high flammability and low density that decided applications in the storage of energy and fuel cells.
Rather, we see how hydrogen is involved in a range of chemical reactions from the synthesis of ammonia to refining and environmental remediation. In our exploration of hydrogen use in transportation and agriculture, we also note the curious behavior at cryogenic temperatures of ortho and parahydrogen, which manifests itself in ways that seem to depend on quantum mechanics and spectroscopy.
Join us in shedding light on the core of hydrogen in the development of our technological environment and, in the end, perhaps leading us to a future development that is sustainable and derived from the imagination and discovery of science.
Preparation of Hydrogen: There are a number of methods for preparing dihydrogen from metals and metal hydrides.
[1]
Cathode Reaction
2H++2e→H2
Anode Reaction
H2O−2e−→2H++1/2O2
Hydrogen gas is formed at the cathode while Oxygen is formed at the anode.
Twice as much Hydrogen as Oxygen is formed.
At Anode: 2Cl−→Cl2+2e−
At cathode : 2H2O(l)+2e−→H2( g)+2OH−(aq)
Overall reaction is
2Na+(aq)+2Cl−(aq)+2H2O(l)→Cl2(g)+H2(g)+2Na+(aq)+2OH−(aq)
By the reaction of Zn with aqueous alkali: Hydrogen can also be prepared by the reaction of zinc with aqueous alkali.
Zn(s) Zinc +2NaOH(aq) Sodium hydroxide → Heat Na2ZnO2(aq)+H2(g)↑ Sodium zincate Hydrogen Zn(s)+ dil. 2HCl(aq) Hydrochloric acid ⟶ZnCl2(aq) Zinc chloride +H2( g)↑ (dil.)
CnH2n+2+nH2O→Ni1270 KnCO+(2n+1)H2
The mixture of CO and H2 is called water gas. As this mixture of CO and H2 is used for the synthesis of methanol and a number of hydrocarbons, it is also called synthesis gas or 'syngas'.
The process of producing 'syngas' from coal is called 'coal gasification.
C+H2O→1270 KCO+H2
CO(g)+H2O(g)673 K catalyst CO2( g)+H2( g)
This is called the water-gas shift reaction.
Physical Properties of Hydrogen: Dihydrogen is a colorless, odorless, tasteless, combustible gas. It is lighter than air and insoluble in water. The electronegativity of hydrogen is in between metals and non-metals so it behaves as both electropositive and electronegative.
Disadvantage: A leak not only means a loss of hydrogen but is, in addition, a decided hazard because of the inflammability and very wide explosive limits that hydrogen possesses. These limits are much wider than for most gases.
The list of physical properties of Hydrogen and its isotopes are mentioned in the table below:
H-H bond Enthalpy: The H–H bond dissociation enthalpy is the highest for a single bond between two atoms of any element. It is because of this factor that the dissociation of dihydrogen into its atoms is only ~0.081% around 2000K which increases to 95.5% at 5000K. Also, it is relatively inert at room temperature due to the high H–H bond enthalpy.
(i) loss of the only electron to give H+
(ii) gain of an electron to form H–
(iii) sharing electrons to form a single covalent bond.
The chemistry of dihydrogen can be illustrated by the following reactions:
H2(g)+X2(g)→2HX(g)(X=F,Cl,Br,I)
3H2( g)+N2( g)→Fe673 K,200 atm2NH3( g);ΔH⊖=−92.6kjmol−1
This is the method for the manufacture of ammonia by the Haber process.
2H2( g)+O2( g)→2H2O(ℓ)ΔH∘=−285.9KJ/mol
Reactions with metals: Many metals, combine at a high temperature to yield the corresponding hydrides
H2( g)+2M(g)→2MH(s) where M is an alkali metal
Hydrogen reacts with many organic compounds in the presence of catalysts to give useful hydrogenated products of commercial importance. For example :
H2+RCH2CH2CHO→RCH2CH2CH2OH
H2+CO+RCH=CH2→RCH2CH2CHO
The various uses of dihydrogen are as follows:
In a molecule of hydrogen when the spin of both H-atoms is in the same direction, they are known as ortho hydrogen.
In a molecule of hydrogen when the spin of both H-atoms is in the opposite direction, they are known as para-hydrogen.
Recommended topic video on(Dihydrogen)
Example 1:
Question:
Calculate the volume of hydrogen gas produced at STP when 10 grams of zinc reacts with excess dilute sulfuric acid.
Solution:
- Moles of zinc = \( \frac{10 \text{ g}}{65.38 \text{ g/mol}} = 0.153 \text{ mol} \)
- Volume of hydrogen gas at STP = \( 0.153 \text{ mol} \times 22.4 \text{ L/mol} = 3.43 \text{ L} \)
Example 2:
Question:
If 5.6 grams of water is electrolyzed using platinum electrodes, calculate the volume of oxygen gas produced at STP.
Solution:
- Moles of water = \( \frac{5.6 \text{ g}}{18.015 \text{ g/mol}} = 0.311 \text{ mol} \)
- Moles of oxygen gas = \( 0.5 \times 0.311 \text{ mol} = 0.156 \text{ mol} \)
- Volume of oxygen gas at STP = \( 0.156 \text{ mol} \times 22.4 \text{ L/mol} = 3.50 \text{ L} \)
These examples demonstrate how to calculate the volume of gases produced in chemical reactions and electrolysis experiments using simple stoichiometry and gas laws.
The importance of hydrogen goes beyond just being an element. Its influence ranges from the roots of chemistry to the most modern of applications among boundaries of science, industry, and the environment. In showing its potential, hydrogen will play a key role in moving sustainable technologies forward and overcoming global challenges.
Frequently Asked Questions
1. How is hydrogen mainly produced?
Hydrogen mainly comes from the steam reforming of natural gas and electrolysis of water where, through chemical reactions, the liberalization of hydrogen gas happens.
2. How does hydrogen contribute to clean energy?
Hydrogen fuels fuel cells in electrical vehicles and can be made from renewable resources, thus creating a clean alternative to fossil fuels.
3. What are Ortho and Para Hydrogen, and why are they important?
Ortho and Para hydrogen represent nuclear spin isomers of hydrogen that, at very low temperatures, show different properties. These properties make them very important in precise spectroscopy or when involved in cryogenic applications.
4. What are some of the significant chemical reactions of Hydrogen?
Hydrogen reacts in basic industrial processes with oxygen to form water and nitrogen to produce ammonia.
5. What are the environmental benefits of hydrogen?
Hydrogen can be derived from renewable sources and, when fed into fuel cells, will give a minimal amount of emission of greenhouse gases and thus provide a clean source of energy.
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