Ortho and Para Hydrogen-Introduction, Position in the periodic Table, Special Forms of Hydrogen, Isotopes, Uses, Practice Problems, FAQs

Have you ever visited a candy shop? What did you observe there? Candies, confectioneries, bonbons, etc all around right!

You may get confused having so many varieties available at a time but they differ in some way.

If it also happens in chemistry then what would you say? It seems quite interesting. You all are familiar with the simplest element of the periodic table ie; hydrogen. Have you thought hydrogen also has different forms? Yes, this is true like candies, hydrogen also has different forms which need to be studied about.

Hydrogen has a great important role in chemical reactions and in daily life also. Hydrogen makes up more than 90% of all of the atoms, which equals three-quarters of the mass of the universe, The element also occurs in the stars. It powers the universe through the proton-proton reaction and the carbon-nitrogen cycle which are fundamental to the universe. Stellar hydrogen fusion processes release huge amounts of energy as they combine hydrogen atoms to form helium. 

Let us begin with the forms of hydrogen and learn more about this unique element.

Table of content:

• Chemistry of Hydrogen
• Position of Hydrogen in the Periodic Table
• Special forms of hydrogen
• Isotopes
• Uses
• Practice problems
• FAQs

Chemistry of Hydrogen

Hydrogen has the simplest atomic structure among all the elements around us in nature. In the atomic form, it consists of only one proton, one electron, and zero neutrons. The electronic  configuration of H is 1s1. In the elemental form, it exists as a diatomic (H2) molecule and is known as dihydrogen.

Position of Hydrogen in the periodic table

Hydrogen is the very first element in the periodic table. There is still an ongoing debate over its proposed placement due to its tendency to both gain and as well as lose an electron.

Hydrogen is placed in group 1 because of the following reasons:

• Hydrogen has an electronic configuration  of 1s¹, i.e., one electron in its valence shell.
• It forms a unipositive ion H⁺(protonium ion) like other group 1 elements (Li⁺ and Na⁺).
• It has a valency of 1.
• It forms oxides, halides, and sulphides like other alkali metals.
• It is a good reducing agent (in atomic as well as molecular states) like other alkali metals.
   

Hydrogen also Resembles Halogens.

• It is a diatomic molecule (H₂) like halogens (F₂,Cl₂,etc) .
• It also forms a uninegative ion H^-1(hydride ion) like halogen.
• Like halogens, it is short by one electron to the corresponding noble gas configuration, which is 

helium (1s²).

• The ionisation energy of H is very high (1312 kJ mol^-1), which is of the same order as that of the halogens.

Special forms of hydrogen:

There are some special forms of hydrogen available. Let us discuss them.

1. Nascent Hydrogen: Nascent hydrogen is hydrogen at the time of its production. It has a higher activity level (reducing power) than regular hydrogen. Ordinary hydrogen, for example, does not reduce manganese when passed through an acidified potassium permanganate solution of ferric chloride solution. However, when zinc pieces are added, however, both are diminished.

KMnO₄ (aq) (purple) + H₂SO₄ (aq) + H2(g) No reaction

Zn (s) + H₂SO₄ (aq) ZnSO₄ (aq) + 2H(g)

2KMnO₄ (aq) (purple) + 3H₂SO₄ (aq) + 10H K₂SO₄ (aq) + 2MnSO₄ (aq)(colourless) + 8H₂O (l)

It's thought that some of the energy released in the hydrogen-producing reaction is associated with hydrogen molecules, making them hyperactive.

2. Atomic hydrogen: When hydrogen is passed through an electric arc established between two tungsten filaments, hydrogen is dissociated into atoms. This form of hydrogen is known as atomic hydrogen. This can be done using an electric arc.

H₂(g) ⇌ 2H(g)............+104.5 kcal mol^-1

Atomic hydrogen has a life span of 0.3 seconds. It quickly reverts to its original state. This process is highly exothermic and is utilised in welding. This type of hydrogen has a higher activity level than regular hydrogen.

Although atomic hydrogen can only be created at extremely high temperatures, nascent hydrogen can be formed at room temperature. Atomic hydrogen has higher reducing power than nascent hydrogen.

3. Ortho and Para Hydrogen: The hydrogen molecule is diatomic, meaning it has two hydrogen atoms in it. Each atom has one proton in its nucleus, which is surrounded by an electron. The proton, like the electron, spins around an axis. The spins of two protons in a hydrogen molecule might be in the same or opposite directions, giving birth to the ortho and para forms. When the proton spins in the same direction, the form is called ortho hydrogen, and when they spin in different directions, the form is called para hydrogen.

The following table illustrates the differences between the two forms.

Physical qualities such as specific heat, thermal conductivity, boiling temperature, and so on can be used as a differentiating factor between the two forms, but chemical properties are found to be similar. 

Isotopes of Hydrogen
Isotopes are the different forms of the same element, which have the same atomic number (Z) but

different mass numbers (A). Hydrogen has three isotopes: protium or H), deuterium( or D), and tritium( or T ).

Because they have the same electrical configuration 1s1, the three isotopes have identical chemical characteristic. Their physical properties, on the other hand, differ due to atomic mass discrepancies.
The above figure depicts the atomic structures of three isotopes.
The three isotopes react at different rates due to their distinct masses. The isotopic effect refers to the change in attributes caused by atomic mass differences.

Practice Problems: 

Q1. _______________, often known as deuterium, is the second isotope of hydrogen.
A. Heavy water
B. Heavy hydrogen
C. Light water
D. Light hydrogen
Heavy hydrogen, often known as deuterium, is the second isotope of hydrogen. The nucleus contains one proton and one neutron, with an electron orbiting around it.

Q2. Isotopes can be separated from ordinary hydrogen by which of the following methods?
A. From liquid hydrogen:
B. By diffusion
C. By adsorption on charcoal
D. All of the above.
Answer: D

Urey and his colleagues obtained deuterium by evaporating liquid hydrogen near its triple point of 13.9 K under reduced pressure. The diffusion method can be used to isolate deuterium from conventional hydrogen. Because protium is lighter than deuterium, it diffuses more easily.

The diffusion takes place at a lower pressure. This procedure is time-consuming and tedious, yet it yields pure deuterium. On charcoal, protium, the lighter isotope, is adsorbed more rapidly and powerfully. All the mentioned above methods can be used to separate ordinary hydrogen from its isotopes.

Q3. What is the ortho-para hydrogen ratio?
A. 2:1
B. 3:1
C. 1:3
D. 1:2
Answer: B
The spins of two protons in a hydrogen molecule might be in the same or opposite directions, giving birth to the ortho and para forms. When the proton spins in the same direction, the form is called ortho hydrogen, and when they spin in different directions, the form is called para hydrogen.
Under normal air circumstances, ordinary hydrogen is 75 % ortho and 25% para-hydrogen is present. The ratio of ortho to para-hydrogen comes out to be 3:1.

Q4. Synthesis gas or syngas is a mixture of
A. CO and H₂
B. CO and H₂O
C. H₂ and CO₂
D. H₂O and CO₂
Answer: (A)
The mixture of CO and H₂ is known as water gas. Because this mixture is employed in the production of methanol and a number of hydrocarbons, it is also known as synthesis gas or syngas.

Frequently asked questions-FAQs: 

Q1. Who was the first to discover the presence of isotopes?
Answer: Bleakney and Gould verified the occurrence of this isotope in 1934 using spectrometric experiments on deuterium-rich materials. It is found in very small amounts in regular hydrogen, i.e. 7 parts per 107 parts of common hydrogen.

Q2. What is the current application of green hydrogen?
Answer: Green hydrogen is employed in a variety of industries. One of the most important is mobility, as green hydrogen is a fuel that only creates water as a by-product. Chemical, petrochemical and steel industries also use it. In addition, progress is being made in terms of its application to in-home energy and heating supplies.

Q3. Why is hydrogen seen as a long-term fuel?
Answer:  Hydrogen can be made from a variety of domestically available materials. The majority of hydrogen presently comes from fossil sources, mostly natural gas. Hydrogen is now produced using electricity from the grid or renewable sources such as biomass, geothermal, solar, or wind. In the long run, when new technologies make alternative production methods cost-competitive, solar energy and biomass can be used more directly to generate hydrogen. The only product emitted by vehicles running on green hydrogen is water, rather than CO2. Hence we can say that hydrogen is seen as a long-term environmental friendly fuel.

Q4. What is Deuterium Depleted Water?
Answer: Water containing Deuterium less than its natural abundance ( <125 ppm) is called Deuterium Depleted Water. It is getting popularized as adjuvant therapy for cancer. Deuterium is a naturally occurring, stable (non-radioactive) hydrogen isotope containing one proton and one neutron in its nucleus. Ordinary hydrogen (protium) has only one proton and no neutron in its nucleus. As a result, deuterium atoms have roughly double the atomic mass of typical hydrogen atoms. Heavy water is made up of water molecules that have two deuterium atoms rather than two hydrogen atoms

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