The following Topics and Sub-Topics are covered in this chapter and are available on MSVgo:
The following Topics and Sub-Topics are covered in this chapter and are available on MSVgo:
Introduction
You might have heard about the element hydrogen in previous classes. It is the basic and most abundant element among all the elements in the universe. Hydrogen atoms make up over 90% of all the atoms in the universe. Its chemical symbol is H. It is a unique element, and it is of great industrial importance as you will learn further in this topic.
Hydrogen has atomic number one, and it is the first and smallest element in the periodic table. It has only one shell, i.e ‘K’ shell, and has only one electron orbiting its shell. The electronic configuration of hydrogen is 1s.
Hydrogen exhibits dual nature due to its only electron present in the outermost shell. So, it can both gain or lose an electron. It shows alkali metals’ properties that gain an electron to form unipositive ions and show the properties of halogens that lose an electron to form uninegative ions.
Although hydrogen has a resemblance with alkali metals and halogens, it differs from them. Hydrogen is less reactive than halogens, and it doesn’t show metallic properties. Hence, it is best placed separately in the periodic table.
Physical Properties
Chemical Properties
Due to the strong bond enthalpy of the H–H bond, hydrogen is relatively inert at room temperature.
Atomic hydrogen is produced under an electric arc under high temperatures.
Hydrogen combines with almost every element as Its orbit is incomplete with a single electron.
Isotopes have the same atomic number but a different mass number. Three isotopes of hydrogen are: 1H1 (protium), 2H1 (deuterium), and 3H1 (tritium).
Protium
Protium is the most common isotope of hydrogen. Its mass number is equal to atomic number = 1 because its nucleus has only a single proton. It has no neutron in its nucleus.
Deuterium
Deuterium is also known as heavy hydrogen. Its mass number is two as it has one proton and one neutron in its nucleus. The nucleus of the deuterium is also called the deuteron.
Tritium
Among all isotopes of hydrogen, only Tritium is radioactive and emits low energy. It has one proton and two neutrons in its nucleus.
Allotropes are different structural forms of the same element. There are two allotropes of hydrogen: Orthohydrogen and parahydrogen
Orthohydrogen
In orthohydrogen, molecule spins of both the nuclei are parallel
Parahydrogen
In parahydrogen, molecule spins of both the nuclei are non-parallel
Atomic hydrogen: It is produced as a result of the endothermic reaction of molecular hydrogen. It is very reactive, and it forms hybrids at normal temperature when passed over metals or non-metals except nitrogen.
Nascent hydrogen: it is a free form of hydrogen which is generated during a chemical reaction. It is a powerful reducing agent.
There are various methods for preparing hydrogen:
Laboratory method
This method usually comprises the reaction of hydrochloric acid, in diluted state, with granulated zinc.
Zn + 2HCl → ZnCl2 + H2
Hydrogen can also be prepared when zinc reacts with alkali metals.
Commercial method
The commonly used methods are:
Cathode: 2 H+ (aq) + 2 e− → H2 (g)
Anode: 2 Cl− (aq) → Cl2 (g) + 2 e−
Overall reaction: 2 NaCl (or KCl) + 2 H2O → Cl2 + H2 + 2 NaOH (or KOH)
CH4 + H2O ⇌ CO + 3 H2
The mixture of Carbon monoxide and H2 is also called syngas.
The process of getting ‘syngas’ from coal is called ‘coal gasification’.
Reactions of hydrogen with other elements are as follows:
Hydrogen with halogens: The reaction produces hydrogen halides.
For example hydrogen + chlorine → hydrogen chloride
H2(g) + Cl2(g) → 2HCl(g)
Hydrogen with dioxygen: The reaction gives water.
2H2(g) + O2(g) → 2H2O(l)
Hydrogen with dinitrogen: The reaction results in the formation of ammonia.
N2(g) + 3H2(g) —> 2NH3(g)
Reactions with metals: Hydrogen reacts with metals to form corresponding hybrids.
For example: H2(g) +2M(g) → 2MH(s)
Uses of hydrogen
What is hydrogen used for?
Ans. It is used in the production of vanaspati ghee by the hydrogenation of polyunsaturated vegetable oils. It is used to reduce heavy metal oxides to metals in metallurgical processes. It serves as a fuel in rockets in space science. Hydrogen is also used to produce many organic compounds like methanol.
What is hydrogen made up of?
Ans. Hydrogen is an element that exists naturally as a molecule. Each molecule of hydrogen is made up of two hydrogen atoms.
What are 3 interesting facts about hydrogen?
Ans. The interesting facts about hydrogen are
Who first discovered hydrogen?
Ans. In 1761, Robert Boyle produced hydrogen gas while experimenting, but it wasn’t until 1766 that Henry Cavendish acknowledged it as a separate component.
What are the five physical properties of hydrogen?
Ans. The physical properties of hydrogen are:
Formulae and concepts are critical, and sometimes it’s difficult to understand it by merely reading. Check out videos on MSVgo to understand the concept behind them. MSVgo is a video library based app that explains concepts with examples or explanatory visualizations or animations, which makes learning interesting!
Hydrogen is one of the essential elements in the universe. It is of great importance due to its various uses. In addition to its use as rocket fuel, hydrogen is also being experimented with within the automotive industry.
