Nascent hydrogen refers to hydrogen atoms that are in their atomic state and are highly reactive due to their high energy levels. These atoms are produced by the dissociation of hydrogen molecules or other chemical compounds that contain hydrogen. Because of their high reactivity, nascent hydrogen atoms are capable of participating in chemical reactions that molecular hydrogen cannot. 

• Nascent hydrogen is also called newly born hydrogen.

Nascent Hydrogen - Unleashing a Promising Element in Chemistry

Representation

Nascent hydrogen is typically represented using the chemical symbol H*. The asterisk (*) indicates that the hydrogen atom is in a highly reactive state and is therefore more likely to participate in chemical reactions.

Alternatively, nascent hydrogen may be represented using the symbol [H]. This notation indicates that the hydrogen atom is in a state of high energy and is therefore more reactive than a regular hydrogen atom.

Characteristics of nascent hydrogen

1.Highly reactive: Nascent hydrogen is highly reactive because of its high energy levels. It can react with a wide range of chemical compounds, including unsaturated hydrocarbons, alcohols, aldehydes, ketones, and other functional groups.

2.Short-lived: Nascent hydrogen is short-lived and cannot be isolated in its pure form. It rapidly reacts with other compounds to form stable products.

3.Selective: Nascent hydrogen is selective in its reactions, meaning it can be used to selectively reduce specific functional groups in a molecule while leaving others unaffected.

4.Reducing agent: Nascent hydrogen acts as a powerful reducing agent in chemical reactions. It can reduce functional groups such as carbonyls, nitriles, and nitro groups to form alcohols, amines, and other reduced compounds.

5.Unstable: Nascent hydrogen is unstable and requires special handling to avoid dangerous reactions. It can ignite spontaneously in the presence of air or other oxidizing agents.

6.Generated in situ: Nascent hydrogen is typically generated in situ, meaning it is produced and used immediately in a chemical reaction. This minimizes the risks associated with handling and storing this highly reactive compound.

7.Versatility: Nascent hydrogen can be produced from various sources, including the reaction of metals with acids or the electrolysis of acid solutions. It can also be used in a wide range of chemical reactions, including reduction, hydrogenation, and dehalogenation reactions.

History

In 1801, British chemist William Nicholson discovered that when water was electrolyzed, hydrogen gas was released at the negative electrode (the cathode). This was one of the first examples of nascent hydrogen, as the hydrogen gas produced was in a highly reactive state due to the electrical current that had passed through the water.

In the mid-19th century, French chemist Louis Pasteur observed that nascent hydrogen played an important role in the fermentation of sugars by yeast. He discovered that yeast cells produce an enzyme called invertase, which breaks down sucrose into glucose and fructose. This reaction produces small amounts of nascent hydrogen, which is thought to facilitate the fermentation process.

Formation reactions

1. Sodium reacts with ethanol to form sodium ethoxide and ethanol. Write the balanced chemical equation.

Na + C2H5OH → C2H5ONa + [H]

2. Aluminium reacts with sodium hydroxide to liberate nascent hydrogen.

Write the balanced chemical equation.

Al + 2NaOH  → Na2AlO2 + 2 [H]

3. Zinc reacts with dilute sulfuric acid to form zinc sulphate and nascent hydrogen.

Write the balanced chemical equation.

Zn + dil.  H2SO4 → ZnSO4 + 2 [H]

4. One common method of generating nascent hydrogen is through the reaction of a metal with an acid, such as zinc with hydrochloric acid:

Zn + 2HCl → ZnCl2 +  H2

In this reaction, the zinc metal reacts with hydrochloric acid to produce zinc chloride and hydrogen gas. The hydrogen gas produced is in its nascent state, as it is highly reactive and has a high energy level. Reaction of metals with acids:

Zn + 2HCl → ZnCl2 + 2 [H]

Reactions of nascent hydrogen

Reduction of double bonds:

Nascent hydrogen is commonly used to reduce double bonds in organic compounds, such as alkenes and alkynes, to form corresponding alkanes. The reaction involves the addition of hydrogen atoms to the double bond, resulting in a saturated compound.

Reduction of functional groups:

Nascent hydrogen can also be used to reduce functional groups, such as carbonyl groups, to form alcohols. The reaction involves the addition of hydrogen atoms to the carbonyl group, resulting in the formation of a hydroxyl group.

Dehalogenation:

Nascent hydrogen can be used to dehalogenate organic compounds, such as haloalkanes, to form corresponding alkanes. The reaction involves the addition of hydrogen atoms to the carbon-halogen bond, resulting in the formation of a hydrogen-halogen bond and an alkane.

Nitrogen fixation:

Nascent hydrogen can react with nitrogen gas to form ammonia, a process known as nitrogen fixation. This reaction is an important biological process that is essential for the synthesis of amino acids, nucleotides, and other nitrogen-containing compounds.

The reactivity of nascent hydrogen

• Reactivity of nascent hydrogen-The production of nascent hydrogen is associated with the release of high energy.
• This released energy activates the nascent hydrogen and makes it more energy-rich than that of ordinary occurring molecular hydrogen.
• Because more energy means more reactivity, nascent hydrogen is more reactive than molecular hydrogen.
• The next reason for the higher reactivity of nascent hydrogen is related to the high internal pressure.
• At the time of formation nascent hydrogen is in the form of minute bubbles with high internal pressure which makes it more reactive.

The reactivity of nascent hydrogen can be illustrated by following reactions: 

1. Reaction with Potassium

Zn + dil. H2SO4 → ZnSO4 + 2[H]

2KMnO4 + 3 H2SO4 +10 [H] → K2SO4 + 2MnSO4 + 8H20.

The nascent hydrogen reduces the permanganate solution, which is pink into colorless manganate salt. Ordinary hydrogen don’t react with KMnO4 .

2.Reaction with Ferric chloride

Zn + dil. H2SO4 → ZnSO4 + 2[H]

2[H] + 2FeCl3 → 2FeCl2 + HCl

Nascent hydrogen reduces Ferric chloride( Yellowish brown) into colorless ferrous salt. This reaction is not given by molecular hydrogen.

 Common industrial applications of nascent hydrogen

Hydrogenation of edible oils: Nascent hydrogen is used in the food industry to hydrogenate vegetable oils to form solid fats, such as margarine. This process involves the addition of hydrogen atoms to unsaturated fatty acids to convert them to saturated fatty acids, which increases the shelf life of the oils.

Production of fertilizers: Nascent hydrogen is used in the Haber process to reduce nitrogen gas to form ammonia, which is then used as a precursor to produce fertilizers.

Metal finishing: Nascent hydrogen is used in the electroplating industry to deposit metals, such as silver and gold, onto a substrate. The hydrogen gas produced during the electroplating process acts as a reducing agent, which reduces the metal ions to form a thin layer of metal on the substrate.

Petrochemical industry: Nascent hydrogen is used in the petrochemical industry to reduce unsaturated hydrocarbons to form saturated hydrocarbons, which improves the quality of the final product.

Pharmaceutical industry: Nascent hydrogen is used in the synthesis of various pharmaceutical compounds, such as antibiotics and steroids, where it is used as a reducing agent.

Water treatment: Nascent hydrogen is used in the water treatment industry to remove contaminants, such as chlorine and other oxidants, from water.

Overall, nascent hydrogen is a versatile and useful reagent that finds many industrial applications due to its ability to act as a powerful reducing agent. However, it is highly reactive and must be handled with care to avoid potential hazards.

Differences between nascent hydrogen and atomic hydrogen

Nascent hydrogen refers to hydrogen that is in a highly reactive state due to being freshly generated by a chemical reaction, such as the electrolysis of water or the reaction of a metal with acid. In this state, the hydrogen atoms are often in a high-energy, excited state, and are more likely to participate in chemical reactions.

Atomic hydrogen, on the other hand, refers to hydrogen atoms that have been dissociated from a molecule or compound and exist as individual atoms. These atoms are also highly reactive and can participate in a variety of chemical reactions.

The key difference between nascent hydrogen and atomic hydrogen is in their origin. Nascent hydrogen is generated as a result of a chemical reaction, while atomic hydrogen is produced through the dissociation of a molecule or compound. Additionally, while both forms of hydrogen are highly reactive, nascent hydrogen is generally considered to be more reactive than atomic hydrogen due to its excited state.

In summary, while nascent hydrogen and atomic hydrogen share some similarities, they are distinct concepts that differ in their origin and reactivity.

Can nascent hydrogen kill the germ?

Yes, nascent hydrogen can kill germs due to its high reactivity and ability to react with organic molecules, including those found in bacterial and viral cells. When nascent hydrogen comes into contact with these organic molecules, it can break down their chemical bonds and disrupt their structure, leading to the death of the germ.

Nascent hydrogen has been used in various applications for its antimicrobial properties, including in water treatment, food preservation, and medical sterilization. For example, in water treatment, nascent hydrogen can be produced through electrolysis and used to disinfect water by killing bacteria and viruses. In medical sterilization, nascent hydrogen gas can be used to decontaminate medical instruments and surfaces.

However, it's worth noting that while nascent hydrogen can be effective in killing germs, it is important to use it properly and in appropriate concentrations to avoid potential harmful effects on human health or the environment.

The Environmental Implications of Nascent Hydrogen

One of the primary environmental concerns associated with nascent hydrogen is the energy required to produce it. Most methods of generating nascent hydrogen require the use of electricity, which is often generated from non-renewable sources like fossil fuels. This means that if nascent hydrogen is produced on a large scale, it could contribute to greenhouse gas emissions and other environmental impacts associated with the production and use of non-renewable energy sources.

Another potential environmental impact of nascent hydrogen production is the generation of waste products. Depending on the method of production, the byproducts of nascent hydrogen production could include gases like oxygen or chlorine, which can have harmful effects on the environment and human health if released into the atmosphere.

Additionally, the use of nascent hydrogen in industrial or medical applications could also have environmental implications. For example, if nascent hydrogen is used as a sterilization agent in medical facilities, the wastewater generated from the process could contain chemical residues that could potentially harm the environment or human health if not properly treated.

Despite these potential environmental concerns, nascent hydrogen also has the potential to offer environmental benefits. For example, it could be used as a renewable energy source in fuel cells or in the production of green hydrogen through the use of renewable energy sources like solar or wind power. Nascent hydrogen could also be used as an alternative to traditional chemical disinfectants, which can have harmful effects on the environment and human health if not used properly.