Difference Wiki

Hydrogenation vs. Reduction: What's the Difference?

Edited by Aimie Carlson || By Janet White || Published on December 28, 2023
Hydrogenation is adding hydrogen to a molecule, while reduction is a broader chemical reaction involving the gain of electrons or decrease in oxidation state.

Key Differences

Hydrogenation specifically involves the addition of hydrogen to another molecule, often used to saturate organic compounds. Reduction, however, is a more general term in chemistry that signifies the gain of electrons by a substance, which can involve but is not limited to hydrogen addition.
Hydrogenation is a type of reduction, it's exclusively focused on the incorporation of hydrogen atoms into a molecule. In contrast, reduction can encompass a wider range of processes, including the removal of oxygen, gain of electrons, or increase in hydrogen, but not exclusively hydrogen.
In the context of organic chemistry, hydrogenation is often associated with the conversion of unsaturated compounds to saturated ones by adding hydrogen. Reduction, in a broader sense, could mean any reaction where a molecule, atom, or ion experiences a decrease in its oxidation state.
Hydrogenation is a specific chemical reaction, often catalyzed by metals like palladium or nickel. Reduction, on the other hand, can occur in various ways, such as by chemical reagents, electrochemically, or biologically, and is not limited to the addition of hydrogen.
Both hydrogenation and reduction are integral in industrial and laboratory chemistry. Hydrogenation is key in processes like food oil hardening, while reduction reactions are crucial in numerous synthetic pathways, including hydrogenation itself.

Comparison Chart


Addition of hydrogen to a molecule
Gain of electrons or decrease in oxidation state


Specific to hydrogen addition
Broader, includes various electron-gain reactions

Examples in Organic Chemistry

Saturating unsaturated fats
Reducing a metal oxide to its metal

Common Use Cases

Food industry, organic synthesis
Metal extraction, chemical synthesis


Often uses metal catalysts like palladium
Can occur through various methods, including metals

Hydrogenation and Reduction Definitions


Hydrogenation is the process of adding hydrogen to an unsaturated organic compound.
Margarine is produced by the hydrogenation of vegetable oil.


Reduction is a chemical reaction involving the gain of electrons.
The reduction of iron ore in a blast furnace produces iron.


Hydrogenation typically involves the conversion of liquid oils to solid fats.
The hydrogenation process is used to make vegetable shortening.


In reduction, the oxidation state of a molecule, atom, or ion is decreased.
The reduction of copper(II) oxide with hydrogen yields copper.


Hydrogenation is a chemical reaction that results in the saturation of organic molecules.
Hydrogenation of ethene produces ethane.


Reduction often involves the loss of oxygen from a compound.
The reduction of zinc oxide with carbon yields zinc.


In hydrogenation, hydrogen is added to a compound, often in the presence of a catalyst.
The hydrogenation of nitrobenzene produces aniline.


Reduction can refer to the addition of hydrogen in a broader sense.
The reduction of a ketone results in an alcohol.


Hydrogenation can be used to reduce or eliminate double bonds in organic compounds.
The hydrogenation of acetylene yields ethylene.


Reduction is the half-reaction in a redox (reduction-oxidation) process where electrons are gained.
In electrolysis, reduction at the cathode leads to metal deposition.


(chemistry) The chemical reaction of hydrogen with another substance, especially with an unsaturated organic compound, and usually under the influence of temperature, pressure and catalysts.


The act or process of reducing.


The act of combining with hydrogen, or the state of being so combined.


A chemical process that adds hydrogen atoms to an unsaturated oil;
Food producers use hydrogenation to keep fat from becoming rancid


What is reduction?

Reduction is a chemical reaction where a substance gains electrons or its oxidation state is decreased.

Is hydrogenation used in food processing?

Yes, hydrogenation is used to convert liquid oils into solid fats, like margarine.

Can reduction occur without hydrogen?

Yes, reduction can involve gaining electrons or losing oxygen, not just gaining hydrogen.

What are common catalysts in hydrogenation?

Metals like palladium, nickel, and platinum are common catalysts.

What's a key difference between hydrogenation and other reduction reactions?

Hydrogenation specifically involves adding hydrogen, while reduction is more general.

What is hydrogenation?

Hydrogenation is the chemical process of adding hydrogen to another molecule.

Are all hydrogenation reactions also reduction reactions?

Yes, all hydrogenation reactions are a form of reduction.

Can reduction reactions be reversed?

Yes, through oxidation, which is the opposite process.

Can hydrogenation be used to make biofuels?

Yes, it's used in processing some types of biofuels.

Can hydrogenation occur naturally?

It's primarily an industrial or laboratory process, not common in nature.

Does hydrogenation always require a catalyst?

While not always necessary, a catalyst typically speeds up the reaction.

Is reduction important in metallurgy?

Yes, reduction is crucial in extracting metals from their ores.

Is reduction always a safe process?

It depends on the chemicals involved; some reduction reactions can be hazardous.

Does hydrogenation affect the nutritional value of food?

Yes, it can reduce unsaturated fats, impacting nutritional value.

Can hydrogenation improve food shelf life?

Yes, by converting oils to solids, it can extend shelf life.

What’s an example of reduction in daily life?

Charging a battery involves reduction at the cathode.

Are there environmental concerns with reduction processes?

Yes, especially if toxic reagents or by-products are involved.

Is reduction a part of the water cycle?

No, the water cycle involves physical changes, not redox reactions.

Can hydrogenation be reversed?

Reversing it is challenging and often impractical.

Is reduction used in water treatment?

Yes, in processes like removing heavy metals from water.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

Trending Comparisons

Popular Comparisons

New Comparisons