Effects of Oxidation Reactions in Everyday Life: We can see the effects of oxidation and reduction reactions in daily life. This has a variety of consequences. Some of its instances, such as burning fuels, digestion of food in our bodies, and so on, are boons to humanity and highly beneficial to the continuation of life.

In this article, we have explained the effects of oxidation reactions in everyday life. Do you know, in human bodies, respiration is the oxidation reaction? During this process, the food is oxidised and produces energy. On the other hand, some of its effects are highly harmful, such as air pollution from burning fuels, food rancidification, metal corrosion, etc.

Examples of Oxidation Reactions

The impacts of oxidation reactions can be seen in our daily lives in various ways. Some of them are beneficial, while others have negative consequences. The following are some common instances of oxidation reactions: 

• Respiration is an oxidation reaction that occurs in our bodies. Food is oxidised to produce energy during respiration.
• Combustion or burning of any substance is an oxidation reaction in which energy is always produced. Combustion of various fuels is used in various home and industrial activities as a source of energy.
• Oxidation reactions include the corrosion of active metals.
• When fried foods are exposed to air for an extended period of time, they develop a foul odour and a terrible taste (rancidity).

Oxidation Reactions in Everyday Life

Now let us discuss oxidation reactions in everyday life.

Combustion Reactions

Kerosene, coal, charcoal, wood, etc., bum in the air and undergo combustion. Methane, a major constituent of natural gas, undergoes combustion in excess of oxygen upon heating.

\({\rm{C}}{{\rm{H}}_4} + 2{{\rm{O}}_2} \to {\rm{C}}{{\rm{O}}_2} + 2{{\rm{H}}_2}{\rm{O}}\)

In nature, all combustion reactions are exothermic and redox, meaning they all emit heat energy. The human body can be thought of as a furnace or machine in which various foodstuffs are burned or oxidised. Our bodies continue to function due to the thermal energy that has been generated. Carbohydrates, such as glucose, fructose, and starch, are the body’s primary energy sources. They undergo combustion with oxygen to produce carbon dioxide and water. For example:

\({{\rm{C}}_6}{{\rm{H}}_{12}}{{\rm{O}}_6} + 6{{\rm{O}}_2} \to 6{\rm{C}}{{\rm{O}}_2} + 6{{\rm{H}}_2}{\rm{O}} + {\rm{energy}}\)

There is no flame present in all combustion reactions. Combustion is just oxidation combined with energy release.

The most significant biological reaction that releases energy in cells is respiration. When we breathe, oxygen enters our lungs and travels through thousands of tiny air sacs (alveoli). These air sacs take up a lot of membrane space, and oxygen diffuses into the blood from the membranes. It binds to haemoglobin in red blood cells and travels to millions of cells throughout the body. In these cells, respiration occurs, accompanied by the burning of glucose, which produces carbon dioxide and water.

The energy released during respiration carries out many cell activities and keeps our heart and muscles going since the reaction is exothermic. It also delivers the intended results. It also gives the body the required warmth. Both carbon dioxide and water are reabsorbed into the bloodstream and exhaled. Respiration is a natural process that occurs in the cells of all living things.

Fish use their gills to absorb oxygen dissolved in the water, whereas plants use microscopic pores (stomata) in their leaves to absorb oxygen.

Harmful Effects of Combustion

We have discussed the utility of combustion in releasing energy that our body needs to keep warm and working. However, combustion has harmful effects also. Environmental pollution is basically due to combustion. Poisonous gases like carbon monoxide \(\left( {{\rm{CO}}} \right),\) sulphur dioxide \(\left( {{\rm{S}}{{\rm{O}}_2}} \right),\) sulphur trioxide \(\left( {{\rm{S}}{{\rm{O}}_3}} \right)\) and oxides of nitrogen, etc., are being released into the atmosphere as a result of a variety of combustion reactions that are taking place. They pollute the atmosphere and make our lives miserable.

Corrosion

Corrosion is a slow process in which the surfaces of metallic objects are coated with oxides, hydroxide, carbonate, or sulphide of metal. This leads to the destruction of metal by chemical or electrochemical reactions with the environment. Corrosion may also be defined as the slow degradation of metal surfaces by the action of air, moisture, or a chemical on their surface.

It causes deterioration (damage) to the buildings, bridges, ships, and metal objects, especially iron. Every year we spend a huge amount of money on account of corrosion.

Some of the examples of corrosion are

• Development of Green Coating on Copper
• Tarnishing of Silver
• Rusting of Iron

Corrosion of Copper

Copper articles develop a coating of green-coloured copper carbonate when they are exposed to a humid atmosphere.

Corrosion of Silver

Silver articles lose their lustre and develop a black coating on their surface. This is due to its oxidation to silver sulphide \(\left( {{\rm{A}}{{\rm{g}}_2}{\rm{S}}} \right)\) on reacting with hydrogen sulphide \(\left( {{{\rm{H}}_2}{\rm{S}}} \right)\) in air. This is also known as tarnishing silver.

\(2{\rm{Ag}} + {{\rm{H}}_2}{\rm{S}} \to {\rm{A}}{{\rm{g}}_2}{\rm{S}} + {{\rm{H}}_2}\)

Corrosion of Iron

The most common form of corrosion is rusting of iron metal. When an iron article remains exposed to moist air for a considerable time, its surface gets covered with a brown, flaky, and non-sticky substance called rust.

Rust is a hydrated ferric oxide \(\left( {{\rm{F}}{{\rm{e}}_2}{{\rm{O}}_3}.{\rm{x}}{{\rm{H}}_2}{\rm{O}}} \right).\) It is formed due to oxygen gas and water vapour present in the air on the iron surface. It can be represented as follows:

\(4{\rm{Fe}} + 3{{\rm{O}}_2} + 2{\rm{x}}{{\rm{H}}_2}{\rm{O}} \to 2{\rm{F}}{{\rm{e}}_2}{{\rm{O}}_3}.{\rm{x}}{{\rm{H}}_2}{\rm{O}}\)

In this reaction, the number of water molecules \((x)\) in the rust varies. Rust is a soft and porous substance that slowly falls off the surface of an iron object, and the iron below it starts rusting. It shows that rusting or corrosion of iron is a continuous process that eats up the whole iron object if not prevented.

Corrosion or rusting weakens the iron and steel objects and structures such as car bodies, bridges, railing, ships, etc.

Prevention of Corrosion

Corrosion of metals is a serious problem, and various measures are taken to prevent it. The main principle behind each method is not allowing the metal surface to come in contact with moisture and air. Few methods of prevention of corrosion are given below:

• Corrosion of metals can be prevented by coating their surfaces with paint or varnish.
• Movable parts of the machinery are prevented from corrosion by the application of oil or grease.
• Corrosion of metals can also be prevented by coating their surface with non-corrosive metals. For example,
  • Corrosion of copper can be prevented by coating it with tin.
  • Metallic articles can be electroplated with noble metals like silver and gold.
• Metals like aluminium can be coated with a thin, strong layer of their oxides. This passive layer protects it from corrosion. The process is known as anodising.
• Corrosion of some metals can be prevented by converting them into alloys. For example, iron can be converted into stainless steel.
• Rusting of iron can also be prevented by covering its surface with a layer of more reactive metal which prevents iron from oxidation. Zinc is often used for covering iron, and the process is called galvanisation. It is an effective method of protecting iron because even if the surface is scratched, the zinc still protects it.

Rancidity

Oxidation has a damaging effect on our food and eatables. Atmospheric oxidation deteriorates stored foodstuffs containing fats and oils and makes them unfit for human use. The foodstuffs containing fats and oils when stored for a long time develop unpleasant smells and bad tastes due to aerial oxidation of fats and oils. This phenomenon of slow aerial oxidation of fats and oils leading to unpleasant smells and bad tastes in them is called ‘rancidity.’

Such fats and oils are said to be ‘rancid.’ The rancid fats and oils give an unpleasant smell and bad taste; therefore, rancid foodstuffs should not be used as they become harmful to the human body. Rancidity in foodstuffs is not desirable and must be checked.

Methods of Preventing Rancidity

The main cause of rancidity is the oxidation of fats and oils present in food. To prevent rancidity, the oils/fats containing food must be prevented from oxidation. The various methods used for the prevention or retardation of rancidity are:

• The Use of Anti-oxidants retards the oxidation of oil or fat present in food. These are the substances that have a strong tendency to get oxidised. These themselves get oxidised and prevent the oxidation of food materials. Common anti-oxidants are BHA (Butylated hydroxyanisole)and BHT (Butylated hydroxytoluene).
  
• Packing in Nitrogen: In some packed foodstuffs, such as potato chips, the plastic bags are filled with unreactive gas nitrogen so that no air or oxygen is available to bring about the oxidation of food and make it rancid.
  
• Keeping in Refrigerator: This is a common method used at our house. When the food is kept in a refrigerator, the oxidation of fats and oils in the food is slowed down due to low temperature, thereby reducing the rate of rancidity.
  
• Storing in Air-Tight Containers: When food is stored in air-tight containers, there is very little exposure to oxygen, and so the oxidation of fats and oils in the food is slowed down, and hence rancidity rate is retarded.
  
• Storing Foods Away from Light: When the food is stored away from light, the oxidation of fats and oils in the food is, and hence rancidity rate is retarded.
  
• Vacuum Packing: In many cases, after packing the food, the container is evacuated before sealing. This is done because no air or oxygen will be available to oxidise food to make it rancid.

Summary

Oxidation has a damaging effect on metals as well as on food. The damaging effect of oxidation on metals is studied as corrosion, and that on food is studied as rancidity. Thus, two common effects of oxidation reactions observed in daily life are corrosion of metals and rancidity of food. The oxidation caused by the oxygen of the air is sometimes also known as aerial oxidation. This article taught you about rancidity and its prevention, corrosion, and prevention in our everyday lives.

FAQs on Effects of Oxidation Reactions in Everyday Life

Q.1: What are the effects of oxidation reactions in everyday life?
Ans: Oxidation reactions involve the loss of electrons or the addition of oxygen. Oxidation occurs in many processes of our day-to-day life, such as respiration, combustion, and photosynthesis in plants. Oxidation takes place in fats and oils and makes them rancid. That’s why nitrogen gas is filled in potato packets to keep them fresh for a long time; otherwise, they get rancid quickly by oxidation.

Q.2: Rancidity is a term used to spoil cooked food materials when kept for a long time in the open. Suggest some methods to prevent such a process from proceeding.
Ans: Various methods can prevent rancidity:
(i) Use of anti-oxidants.
(ii) Packaging of food in bags flushed with nitrogen gas.
(iii) Storing food in refrigerators & air-tight containers.
(iv) Keeping food away from sunlight.

Q.3: Explain the oxidation and reduction in terms of gain or loss of oxygen with two examples each.
Ans: (a) Oxidation is the gain of oxygen by a substance. For example,
(i) \(2{\rm{Mg}} + {{\rm{O}}_2} \to 2{\rm{MgO}}\)
(Oxidation of \({\rm{Mg}}\) to \({\rm{MgO}}\))
(ii) \({\rm{C}} + {{\rm{O}}_2} \to {\rm{C}}{{\rm{O}}_2}\)
(Oxidation of \({\rm{C}}\) to \({\rm{C}}{{\rm{O}}_2}\))
(b) Reduction is the loss of oxygen from a substance.
(i) \(2{\rm{HgO}} \to 2{\rm{Hg}} + {{\rm{O}}_2}\)
(Reduction of \({\rm{HgO}}\) to \({\rm{Hg}}\))
(ii) \({\rm{CuO}} + {\rm{C}} \to {\rm{Cu}} + {\rm{CO}}\)
(Reduction of \({\rm{CuO}}\) to \({\rm{Cu}}\))

Q.4: What are the effects of oxidation and reduction reactions?
Ans: An oxidation-reduction reaction is any chemical reaction in which the oxidation number of a molecule, atom, or ion changes by gaining or losing an electron. Redox reactions are common and vital to some of the basic functions of life, including photosynthesis, combustion, and corrosion or rusting.

Q.5: What is an example of useful oxidation?
Ans: An oxidation reaction in which energy is always created is the combustion or burning of any substance. Combustion of various fuels is used in various home and industrial activities as a source of energy.

Q.6: List any two effects of oxidation reactions in everyday life.
Ans: The effects of oxidation reaction on everyday life are corrosion of metal, rancidity and combustion.