Redox Reactions - Examples, Types, Applications, Balancing

Edited By Shivani Poonia | Updated on Jul 02, 2025 07:58 PM IST

Redox reaction includes reducing and oxidizing agents which are the main components of this reaction
Oxidizing Agent- The substance that gains electrons and gets reduced. It causes another substance to be oxidized.
Reducing Agent- The substance that loses electrons and gets oxidized. It causes another substance to be reduced.

This Story also Contains

What Is Redox Reaction
Redox Reaction:
Types Of Redox Reaction
Some Solved Examples
Summary

Redox Reactions - Examples, Types, Applications, Balancing

What Is Redox Reaction

A redox (reduction-oxidation) reaction involves the transfer of electrons between two substances. This type of reaction is fundamental in chemistry and is central to many biological and industrial processes.

- Oxidation: The process in which a substance loses electrons. This leads to an increase in the oxidation state of the substance.
- *Reduction: The process in which a substance gains electrons. This leads to a decrease in the oxidation state of the substance.

Redox Reaction:

Any reaction, in which the electrons are exchanged between atoms or ions, represents a simultaneous process of oxidation and reduction is called a Redox Reaction.

A⁰ + B⁰ → A⁺ + B^-

Here, A to A⁺, Loss of electron ( Oxidation )

And B to B^-, Gain of electron ( Reduction )

Some examples include:

$\mathrm{Zn}(\mathrm{s})+\mathrm{CuSO}_4(\mathrm{aq}) \rightarrow \mathrm{ZnSO}_4(\mathrm{aq})+\mathrm{Cu}(\mathrm{s})$ (Metal displacement)
$\mathrm{Na}(\mathrm{s})+\mathrm{H}_2 \mathrm{O}(\mathrm{l}) \rightarrow \mathrm{NaOH}(\mathrm{aq})+\mathrm{H}_2(\mathrm{~g})($ Non - Metal displacement $)$

Some other examples of redox reactions in which oxidation and reduction are happening simultaneously.

$\mathrm{P}_4(\mathrm{~s})+3 \mathrm{OH}^{-}(\mathrm{aq})+3 \mathrm{H}_2 \mathrm{O}(\mathrm{l}) \rightarrow \mathrm{PH}_3(\mathrm{~g})+3 \mathrm{H}_2 \mathrm{PO}_2^{-}$

Types Of Redox Reaction

The different types of redox reactions are:

Decomposition Reaction
Combination Reaction
Displacement Reaction
Disproportionation Reactions

Decomposition Reaction

This is the reaction that involves the breakdown of a compound into different compounds. Some examples of this type of reaction are:

$2 \mathrm{H}_2 \mathrm{O}(\mathrm{l}) \xrightarrow{\Delta} 2 \mathrm{H}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g})$$2 \mathrm{KClO}_3(\mathrm{~s}) \xrightarrow{\Delta} 2 \mathrm{KCl}(\mathrm{s})+3 \mathrm{O}_2(\mathrm{~g})$

This must be noted here that all decomposition reactions are not redox reactions. For example, the decomposition of calcium carbonate is not a redox reaction.$\mathrm{CaCO}_3(\mathrm{~s}) \xrightarrow{\Delta} \mathrm{CaO}(\mathrm{s})+\mathrm{CO}_2(\mathrm{~g})$

Combination Reaction

These types of reactions are the opposite of decomposition reactions and hence involve the combination of two species to form a single compound. Some examples include:
$\mathrm{C}(\mathrm{s})+\mathrm{O}_2(\mathrm{~g}) \xrightarrow{\Delta} \mathrm{CO}_2(\mathrm{~g})$$3 M g(s)+N_2(g) \rightarrow M g_3 N_2(s)$

Displacement Reaction

Displacement reactions, also known as replacement reactions, involve compounds and the replacement of elements. They occur as single and double replacement reactions. In other words, in these type of reactions, an atom or an ion in a compound is substituted by another element.

Some examples include:

Disproportionation Reactions

Disproportionation reactions are those reactions in which a single element in one oxidation state is simultaneously oxidized and reduced. Some examples include:

$\mathrm{P}_4(\mathrm{~s})+3 \mathrm{OH}^{-}(\mathrm{aq})+3 \mathrm{H}_2 \mathrm{O}(\mathrm{l}) \rightarrow \mathrm{PH}_3(\mathrm{~g})+3 \mathrm{H}_2 \mathrm{PO}_2^{-}$$\mathrm{S}_8(\mathrm{~s})+12 \mathrm{OH}^{-}(\mathrm{aq}) \rightarrow 4 \mathrm{~S}^{2-}(\mathrm{aq})+2 \mathrm{~S}_2 \mathrm{O}_3^{2-}(\mathrm{aq})+6 \mathrm{H}_2 \mathrm{O}(\mathrm{l})$

Some Solved Examples

Example.1

1. Which of the following is a redox reaction?

1)$\mathrm{NaCl}+\mathrm{KNO}_3 \rightarrow \mathrm{NaNO}_3+\mathrm{KCl}$

2)$\mathrm{CaC}_2 \mathrm{O}_4+2 \mathrm{HCl} \rightarrow \mathrm{CaCl}_2+\mathrm{H}_2 \mathrm{C}_2 \mathrm{O}_4$

3)$\mathrm{Mg}(\mathrm{OH})_2+2 \mathrm{NH}_4 \mathrm{Cl} \rightarrow \mathrm{MgCl}_2+2 \mathrm{NH}_4 \mathrm{OH}$

4) (correct)$\mathrm{Zn}+2 \mathrm{AgCN} \rightarrow 2 \mathrm{Ag}+\mathrm{Zn}(\mathrm{CN})_2$

Solution

In a Redox Reaction, the oxidation states of the constituents should change.

Keeping that in mind, let us look at each reaction:

$\stackrel{+1-1}{\mathrm{NaCl}}+\stackrel{+1+5-2}{\mathrm{KNN}} \stackrel{+}{\mathrm{N}}_3 \rightarrow \stackrel{+1+5-2}{\mathrm{Na}} \mathrm{N}_3+\stackrel{+1-1}{\mathrm{KCl}}$

There is no change in the oxidation states.

$\mathrm{CaC}_2 \mathrm{O}_4+2 \mathrm{HCl} \rightarrow \mathrm{CaCl}_2+\mathrm{H}_2 \mathrm{C}_2 \mathrm{O}_4$

There is no change in the oxidation states.

$\mathrm{Mg}(\mathrm{OH})_2+2 \mathrm{NH}_4 \mathrm{Cl} \rightarrow \mathrm{MgCl}_2+2 \mathrm{~N} \mathrm{H}_4 \mathrm{OH}$

There is no change in the oxidation states.

Finally,

$\stackrel{0}{\mathrm{Zn}}+2 \stackrel{+1}{\mathrm{Ag}} \stackrel{+2-3}{\mathrm{~N}} \rightarrow 2 \stackrel{0}{\mathrm{Ag}}+\stackrel{+2}{\mathrm{Zn}}(\stackrel{+2-3}{\mathrm{C}})_2$

There is a change in the oxidation states of the constituents.

$\therefore$ The last reaction is redox.

The oxidation states show a change only in reaction (d).

Hence, the answer is the option (4).

Example.2

2. Which of the following reactions is an example of a redox reaction?

1)XeF₆ + H₂O → XeOF₄ + 2HF

2)XeF₆ + 2H₂O → XeO₂F₂ + 4HF

3) (correct)XeF₄ + O₂F₂ → XeF₆ + O₂

4)XeF₂ + PF₅ → [XeF]⁺ PF₆⁻

Solution

In the given reactions:

$\mathrm{XeF}_6+\mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{XeOF}_4+2 \mathrm{HF}$

The oxidation states are:

$\mathrm{XeF}_6+\mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{XeOF}_4+2 \mathrm{HF}$

There is no change in the oxidation states of any of the reactants.

$\therefore$ The above is not a redox reaction.

Similarly, $\mathrm{XeF}_6+2 \mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{XeO}_2 \mathrm{~F}_2+4 \mathrm{HF}$

$\therefore$ Above is not a redox reaction

In the reaction,

(+2) (-1) (+5) (-1) (+2) (-1) (+5) (-1)

$X e F_2+P F_5 \rightarrow[X e F]^{+}\left[P F_6\right]$

$\therefore$ Above is not a redox reaction

Now,

+4 -1 +1 -1 +6 -1 0

$X e F_4+O_2 F_2 \rightarrow X e F_6+O_1$

The oxidation state of Xe changed from +4 to +6 and that of oxygen changed from (+1) to 0

This is an example of a redox reaction.

Hence, the answer is an option (3).

Example.3

3. In the following reaction which species undergoes reduction?

$\left.2 \mathrm{Na}_{(} \mathrm{s}\right)+\mathrm{H}_{2(g)} \rightarrow 2 \mathrm{NaH}_{(\mathrm{s}}$

1)Na

2) (correct)H

3)NaH

4)Not a redox reaction.

Solution

Redox Reaction -

Redox reaction is a class of reactions in which oxidation and reduction reactions occur simultaneously.

Since hydrogen is more electronegative than sodium, so hydrogen undergoes reduction.

Hence, the answer is the option (2).

Example.4

4. In the following reaction, which species undergoes oxidation?

$\mathrm{Cl}_{2(g)}+3 \mathrm{~F}_{2(g)} \rightarrow 2 \mathrm{ClF}_{3(g)}$

1) (correct)Cl

2)F

3)Neither

4)The reaction is not redox

Solution

Redox Reaction -

Redox reaction is a class of reactions in which oxidation and reduction reactions occur simultaneously.

Since fluorine is more electronegative than chlorine, so chlorine undergoes oxidation.

Hence, the answer is the option (1).

Example.5

5. On heating $\mathrm{KClO}_2$ it gives KCl and O₂ This reaction is known as

1)Oxidation

2)Reduction

3)Disproportionation

4) (correct)Redox

Solution

Redox reaction is a class of reactions in which oxidation and reduction reactions occur simultaneously.

In the reaction :

$2 \mathrm{KClO}_3 \rightarrow 2 \mathrm{KCl}+3 \mathrm{O}_2$

Cl is reduced from +5 to -1 oxidation state and O is oxidized from -2 to 0 oxidation state.

So, it is an example of a redox reaction.

Hence, the answer is the option (4).

Summary

Redox reactions are essential in mining for extracting metals, processing ores, managing environmental impacts, and optimizing energy use. They are fundamental to both the technical and environmental aspects of mining operations. Redox reactions are often exothermic or endothermic, impacting the energy requirements of mining processes. Redox reactions help control the acidity or alkalinity of the solution, optimizing the extraction and concentration of desired metals.

Frequently Asked Questions (FAQs)

1. What's the difference between oxidation and reduction?

Oxidation is the loss of electrons, resulting in an increase in oxidation state. Reduction is the gain of electrons, resulting in a decrease in oxidation state. An easy way to remember is "OIL RIG": Oxidation Is Loss, Reduction Is Gain (of electrons).

2. What are half-reactions in redox processes?

Half-reactions are the separate oxidation and reduction processes that make up a complete redox reaction. The oxidation half-reaction shows the loss of electrons, while the reduction half-reaction shows the gain of electrons. When combined, they form the complete redox reaction.

3. What is a reducing agent?

A reducing agent, or reductant, is a species that donates electrons to another species, causing that species to be reduced. The reducing agent itself is oxidized in the process. Examples include hydrogen, carbon, and sodium borohydride.

4. What is the difference between oxidation number and oxidation state?

The terms oxidation number and oxidation state are often used interchangeably. Both refer to the degree of oxidation of an atom in a chemical compound, representing the hypothetical charge an atom would have if all bonds to atoms of different elements were completely ionic.

5. Why is balancing redox reactions important?

Balancing redox reactions is crucial to ensure that mass and charge are conserved. It helps in understanding the stoichiometry of the reaction, predicting products, and calculating the amount of reactants needed or products formed. Proper balancing is essential for applications in electrochemistry and industrial processes.

6. How can you identify a redox reaction?

You can identify a redox reaction by looking for changes in oxidation states of elements involved. If at least one element's oxidation state increases (oxidation) and another's decreases (reduction), it's a redox reaction. You can also look for electron transfer between species.

7. Can a single element undergo both oxidation and reduction in the same reaction?

Yes, this is called disproportionation. In these reactions, a single element is both oxidized and reduced. For example, when chlorine gas reacts with water, some chlorine atoms are oxidized to hypochlorite ions while others are reduced to chloride ions.

8. How does electronegativity relate to redox reactions?

Electronegativity, the ability of an atom to attract electrons, plays a crucial role in redox reactions. Generally, atoms with higher electronegativity tend to gain electrons (be reduced) while those with lower electronegativity tend to lose electrons (be oxidized).

9. What is an oxidizing agent?

An oxidizing agent, or oxidant, is a species that accepts electrons from another species, causing that species to be oxidized. The oxidizing agent itself is reduced in the process. Examples include oxygen, chlorine, and potassium permanganate.

10. What is the significance of redox reactions in daily life?

Redox reactions are ubiquitous in daily life. They are crucial in energy production (batteries, fuel cells), metabolism (cellular respiration), photosynthesis, corrosion (rusting), bleaching, and many industrial processes. Understanding redox reactions helps us comprehend numerous natural and technological processes around us.

11. What is a redox reaction?

A redox reaction, short for reduction-oxidation reaction, is a type of chemical reaction where electrons are transferred between species. One species loses electrons (oxidation) while another gains electrons (reduction). This process changes the oxidation states of the atoms involved.

12. How do redox reactions relate to electron transfer?

Redox reactions fundamentally involve the transfer of electrons between species. The species losing electrons (oxidized) transfers them to the species gaining electrons (reduced). This electron transfer is the essence of redox reactions and is responsible for the changes in oxidation states observed.

13. What is the importance of redox reactions in cellular respiration?

Cellular respiration is essentially a controlled, step-wise redox process. Glucose is oxidized (loses electrons) while oxygen is reduced (gains electrons). This electron transfer is coupled with ATP production, providing energy for cellular processes. The electrons pass through an electron transport chain, driving ATP synthesis.

14. What is a redox titration?

A redox titration is an analytical technique used to determine the concentration of an analyte based on a redox reaction. It involves the controlled addition of a titrant (a solution of known concentration) to a solution containing the analyte until the reaction is complete. The endpoint is often indicated by a color change.

15. What is the connection between redox reactions and antioxidants?

Antioxidants function by undergoing redox reactions. They can donate electrons to reactive oxygen species (free radicals), neutralizing them before they can cause cellular damage. In this process, the antioxidant is oxidized while preventing the oxidation of other important cellular components.

16. How do redox reactions contribute to the nitrogen cycle?

Redox reactions are crucial in the nitrogen cycle. Nitrogen fixation reduces atmospheric N₂ to ammonia. Nitrification oxidizes ammonia to nitrate via nitrite. Denitrification reduces nitrate back to N₂. These redox processes, carried out by different microorganisms, are essential for maintaining the balance of nitrogen in ecosystems.

17. What is the significance of redox reactions in brewing and fermentation?

In brewing and fermentation, redox reactions play a key role. During alcoholic fermentation, glucose is oxidized to ethanol and carbon dioxide. The electrons released in this process are accepted by acetaldehyde, which is reduced to ethanol. Understanding these redox processes is crucial for controlling fermentation in food and beverage production.

18. How do redox reactions apply to bleaching processes?

Bleaching involves redox reactions. Bleaching agents are typically strong oxidizing agents that break down color-causing compounds (chromophores) in stains. For example, chlorine bleach (sodium hypochlorite) oxidizes chromophores, breaking their conjugated double bond systems and eliminating their color-producing properties.

19. What is the role of redox reactions in photography?

Traditional film photography relies on redox reactions. When light hits silver halide crystals in the film, some silver ions are reduced to silver atoms. During development, a reducing agent converts the remaining silver ions in exposed areas to silver, creating the image. Fixing removes unexposed silver halides.

20. What is the importance of redox reactions in water treatment?

Redox reactions are crucial in water treatment. Oxidizing agents like chlorine or ozone are used to kill pathogens and oxidize organic contaminants. Reduction processes can remove certain metal ions. Understanding redox chemistry is essential for designing effective water purification systems.

21. What is the role of redox reactions in electroplating?

Electroplating uses redox reactions to coat one metal with another. In the electrolytic cell, the anode (the metal used for coating) is oxidized, releasing metal ions into the solution. At the cathode (the object being plated), these ions are reduced, depositing the metal coating. This process is used for both decorative and protective purposes.

22. How do redox reactions contribute to the carbon cycle?

Redox reactions are integral to the carbon cycle. In photosynthesis, CO₂ is reduced to form glucose. In respiration and decomposition, organic compounds are oxidized back to CO₂. The burning of fossil fuels is also a redox process, oxidizing hydrocarbons to CO₂ and H₂O. These processes maintain the balance of carbon in the biosphere.

23. How do redox reactions apply to the process of photographic development?

In photographic development, redox reactions convert the latent image to a visible one. The developer solution contains reducing agents that selectively reduce silver ions to metallic silver in areas exposed to light. The oxidation of the developing agent is coupled with the reduction of silver ions, creating the image.

24. What is the role of redox reactions in the human immune system?

Redox reactions play a crucial role in the immune system. White blood cells use oxidative bursts to kill pathogens, producing reactive oxygen species like hydrogen peroxide. Additionally, the body uses antioxidants to neutralize harmful free radicals, which are often byproducts of cellular metabolism or external factors.

25. What is the significance of redox reactions in food preservation?

Redox reactions are important in food preservation. Antioxidants are added to foods to prevent oxidation, which can lead to rancidity in fats or browning in fruits. Conversely, controlled oxidation is used in some preservation methods, such as in the curing of meats, where nitrites are used to prevent bacterial growth.

26. How do redox reactions contribute to the taste of foods?

Redox reactions contribute significantly to food flavors. For example, the Maillard reaction, responsible for the brown color and complex flavors in cooked foods, involves a series of redox reactions between amino acids and reducing sugars. Oxidation can also produce off-flavors in foods, such as the rancid taste in oxidized fats.

27. What is the role of redox reactions in the formation of minerals?

Redox reactions are crucial in mineral formation. Changes in the oxidation state of elements can lead to the precipitation or dissolution of minerals. For example, the formation of many ore deposits involves the reduction of metal ions in solution, leading to the precipitation of metal-bearing minerals.

28. What is the importance of redox reactions in soil chemistry?

Redox reactions in soil affect nutrient availability, pH, and microbial activity. The oxidation state of elements like iron, manganese, and sulfur changes with soil conditions, influencing their solubility and availability to plants. Redox conditions also affect the behavior of contaminants in soil, impacting environmental remediation strategies.

29. How do redox reactions apply to the process of combustion?

Combustion is a rapid redox reaction where a fuel is oxidized by an oxidizer, typically oxygen from the air. The fuel (often a hydrocarbon) loses electrons to oxygen, producing heat and light. For example, in the combustion of methane: CH₄ + 2O₂ → CO₂ + 2H₂O. Understanding this process is crucial for energy production and fire safety.

30. What is the role of redox reactions in the ozone layer?

Redox reactions are central to ozone layer dynamics. Ozone (O₃) is formed when oxygen molecules are split by UV radiation, and the resulting oxygen atoms react with other oxygen molecules. Ozone can be destroyed by reactions with certain pollutants, like chlorofluorocarbons (CFCs), which involve the reduction of ozone and oxidation of the pollutant.

31. How do you determine oxidation numbers?

To determine oxidation numbers, follow these rules: (1) Free elements have an oxidation number of 0, (2) For monatomic ions, the oxidation number equals the charge, (3) The sum of oxidation numbers in a neutral compound is 0, (4) In compounds, certain elements have fixed oxidation numbers (e.g., Group 1 metals are +1). Apply these rules systematically to determine oxidation numbers.

32. What is the role of redox reactions in corrosion?

Corrosion, such as the rusting of iron, is a redox process. In rusting, iron is oxidized by oxygen in the presence of water, forming iron oxides. The iron loses electrons (oxidation) while oxygen gains electrons (reduction). Understanding this process helps in developing corrosion prevention strategies.

33. How are redox reactions used in batteries?

Batteries operate on redox principles. They consist of two half-cells separated by an electrolyte. One electrode undergoes oxidation, releasing electrons, while the other undergoes reduction, accepting electrons. This flow of electrons through an external circuit provides electrical energy. Different types of batteries use different redox couples.

34. What is the difference between galvanic and electrolytic cells?

Galvanic cells (like batteries) produce electricity from spontaneous redox reactions. Electrolytic cells, conversely, use electrical energy to drive non-spontaneous redox reactions. In galvanic cells, the reaction occurs spontaneously, while in electrolytic cells, an external power source is required to make the reaction proceed.

35. How do redox reactions apply to photosynthesis?

Photosynthesis is a complex series of redox reactions. Light energy is used to oxidize water, producing oxygen and electrons. These electrons are then used to reduce carbon dioxide to glucose. The overall process can be seen as the reduction of carbon dioxide using electrons from water, driven by light energy.

36. How do redox reactions relate to the reactivity series of metals?

The reactivity series of metals is based on their tendency to undergo oxidation. More reactive metals (like potassium or sodium) lose electrons more easily and are stronger reducing agents. Less reactive metals (like gold or platinum) are less likely to be oxidized. This series helps predict the outcomes of displacement reactions.

37. How do redox reactions apply to the extraction of metals from ores?

Metal extraction often involves redox reactions. Many metals occur in nature as oxides or other compounds. To obtain the pure metal, these compounds must be reduced. For example, iron oxide is reduced to iron using carbon monoxide in a blast furnace. The carbon monoxide is oxidized to carbon dioxide in this process.

38. What is the role of redox reactions in fuel cells?

Fuel cells generate electricity through redox reactions, similar to batteries but with continuous fuel supply. In a hydrogen fuel cell, hydrogen is oxidized at the anode, releasing electrons. These electrons flow through an external circuit to the cathode, where oxygen is reduced. This process generates electricity and water as a byproduct.

39. How do redox reactions relate to the reactivity of halogens?

The reactivity of halogens is based on their ability to be reduced (gain electrons). Fluorine is the strongest oxidizing agent among halogens as it most readily accepts electrons. The reactivity decreases down the group (F > Cl > Br > I) as the atoms become larger and less able to attract electrons.

40. How are redox reactions involved in the process of respiration?

Respiration is a series of redox reactions. Glucose (the fuel) is gradually oxidized, losing electrons. Oxygen (the final electron acceptor) is reduced to water. The energy released from this electron transfer is used to produce ATP. This process occurs in stages: glycolysis, the citric acid cycle, and the electron transport chain.

41. How do redox reactions apply to the formation of rust?

Rust formation is a redox process. Iron is oxidized by oxygen in the presence of water, forming iron(III) oxide-hydroxide (rust). The iron loses electrons (is oxidized) while oxygen gains electrons (is reduced). This process can be represented as: 4Fe + 3O₂ + 2H₂O → 4Fe(OH)₃.

42. What is the significance of redox reactions in metallurgy?

Redox reactions are fundamental in metallurgy, the science of extracting metals from their ores. Most metals occur in nature as oxides or other compounds and must be reduced to obtain the pure metal. For example, in the extraction of iron, iron oxide is reduced by carbon monoxide in a blast furnace: Fe₂O₃ + 3CO → 2Fe + 3CO₂.

43. How are redox reactions used in breathalyzers?

Breathalyzers use a redox reaction to detect alcohol. Ethanol in the breath is oxidized to acetaldehyde by a chemical such as potassium dichromate. This reaction causes a color change, which is measured to determine the alcohol concentration. The dichromate ion is reduced in this process.

44. What is the connection between redox reactions and fireworks?

The vibrant colors in fireworks are produced through redox reactions. Metal salts are reduced to excited metal atoms, which emit light as they return to their ground state. The oxidizer (often potassium perchlorate) provides oxygen for the reaction, while the fuel (often carbon-based) is oxidized, producing the heat and gases for the explosion.

45. How are redox reactions involved in the process of composting?

Composting involves a series of redox reactions. Microorganisms break down organic matter through oxidation, using oxygen as the electron acceptor. This process releases energy and produces CO₂ and water. The gradual oxidation of complex organic molecules results in the formation of stable humus.

46. How are redox reactions used in chemical analysis?

Redox reactions are widely used in chemical analysis. Redox titrations can determine the concentration of oxidizing or reducing agents in a solution. Potentiometric methods use the potential difference generated by redox reactions to analyze solutions. Redox indicators change color at specific potentials, signaling the endpoint of a titration.

47. How are redox reactions involved in the process of digestion?

Digestion involves numerous redox reactions. Carbohydrates, fats, and proteins are oxidized to release energy. The electrons removed from these nutrients are ultimately transferred to oxygen through the electron transport chain, producing ATP. Antioxidants in our diet