Effects of Oxidation Reactions in Everyday Life

The addition of an oxygen atom to a compound is referred to as oxidation. This process’s inverse is known as reduction and involves the removal of an electron. Biological oxidation is a biological process in which electrons are lost, as opposed to reduction, which involves the gain of electrons. However, oxidation and reduction are linked as a redox reaction, which is an energy-producing reaction within the cell.

Effects of Oxidation Reactions in Everyday Life

Redox changes are significant reactions that have a variety of consequences in our daily lives. Some of its manifestations, such as the combustion of fuels and the digestion of food in our bodies, are boons to humanity and extremely beneficial to the continuation of life. Some of its side effects, on the other hand, are extremely harmful, such as air pollution from burning fuels, food rancidification, metal corrosion, and so on.

Examples of Oxidation Reaction

The effects of oxidation reactions can be seen in a variety of ways in our daily lives. Some of them are advantageous, while others are detrimental. The following are some examples of oxidation reactions:

1. In our bodies, respiration is an oxidation reaction. During respiration, food is oxidized to produce energy.
2. Combustion Reactions: Any substance’s combustion or burning is an oxidation reaction in which energy is always produced. The combustion of various fuels is used as a source of energy in a variety of home and industrial activities.
3. Corrosion of active metals is one of the oxidation reactions.
4. Rancidity: Fried foods develop a foul odour and a terrible taste when exposed to air for an extended period of time.

Combustion Reactions

Kerosene, coal, charcoal, wood, and other materials float in the air and burn. When methane, a major component of natural gas, is heated, it burns with an excess of oxygen.

CH₄ + 2O₂  →  CO₂ + 2H₂O

All combustion reactions in nature are exothermic and redox, which means they all emit heat energy. The human body can be compared to a furnace or machine that burns or oxidises various foods. As a result of the thermal energy that has been generated, our bodies continue to function. Carbohydrates like glucose, fructose, and starch are the body’s primary energy source. They, for example, are combusted with the oxygen we breathe to produce carbon dioxide and water.

C₆H₁₂O₆ + 6O₂  →  6CO₂ + 6H₂O + Energy

In all combustion reactions, there is no flame. Combustion is simply oxidation with energy release. Respiration is the most important biological reaction that releases energy in cells. When we breathe, oxygen enters our lungs and passes through thousands of tiny air sacs (alveoli). These air sacs occupy a significant amount of membrane space, and oxygen diffuses into the blood through the membranes. It binds to haemoglobin in red blood cells before spreading to millions of cells throughout the body. Respiration occurs in these cells, along with the burning of glucose, which produces carbon dioxide and water.

Because the reaction is exothermic, the energy released during respiration powers many cell activities and keeps our heart and muscles working. It also achieves the desired results. It also provides the body with the necessary warmth. Carbon dioxide and water are both reabsorbed into the bloodstream before being exhaled. Respiration is a natural process that occurs in all living things’ cells. Fish use their gills to absorb oxygen dissolved in water, whereas plants absorb oxygen through microscopic pores (stomata) in their leaves.

Corrosion

Corrosion is a slow process in which the surfaces of metallic objects become coated with the metal’s oxides, hydroxide, carbonate, or sulphide. Metal is destroyed as a result of chemical or electrochemical reactions with the environment. 

Corrosion is also defined as the gradual deterioration of metal surfaces caused by the action of air, moisture, or a chemical on their surface. It deteriorates (damages) buildings, bridges, ships, and metal objects, particularly iron. Corrosion can be seen in the following examples:

• Development of green coating on copper
• Tarnishing of silver
• Rusting of iron

Corrosion of some Metals are listed below:

1. Copper: When exposed to a humid environment, copper articles develop a coating of green copper carbonate.
2. Silver: Silver loses its lustre and develops a black coating on its surface. This is because it oxidises to silver sulphide when it reacts with hydrogen sulphide in the air. This is also referred to as tarnishing silver.
3. Iron: Rusting of iron metal is the most common type of corrosion. When an iron object is exposed to moist air for an extended period of time, its surface becomes coated with rust, a brown, flaky, non-sticky substance.

Prevention of Corrosion

Metal corrosion is a serious issue, and various measures are taken to prevent it. The main principle underlying each method is to keep the metal surface away from moisture and air. The following are a few corrosion prevention methods:

1. Metal corrosion can be avoided by coating their surfaces with paint or varnish.
2. The application of oil or grease to moving parts of the machinery prevents corrosion.
3. Metal corrosion can also be avoided by coating the metal’s surface with non-corrosive metals. E.g. Copper corrosion can be avoided by coating it with tin, and metallic objects can be electroplated with noble metals such as silver and gold.
4. Metals, such as aluminium, can be coated with a thin, strong layer of oxides. It is protected from corrosion by this passive layer. Anodizing is the name given to this process.
5. Some metals can be protected from corrosion by converting them into alloys. Iron, for example, can be transformed into stainless steel.
6. Rusting of iron can also be avoided by coating its surface with a layer of a more reactive metal that prevents the oxidation of iron. Galvanization is a process in which zinc is used to cover iron. It is an effective method of protecting iron because the zinc protects it even if the surface is scratched.

Rancidity

Oxidation is harmful to our food and eatables. Atmospheric oxidation degrades stored foods containing fats and oils, rendering them unfit for human consumption. Foods containing fats and oils develop unpleasant odours and bad taste after a long period of storage due to aerial oxidation of fats and oils. 

Rancidity refers to the slow aerial oxidation of fats and oils, which results in an unpleasant odour and taste.

These fats and oils are referred to as ‘rancid.’ Rancid fats and oils have an unpleasant odour and taste, and as a result, rancid foodstuffs should not be used because they are harmful to the human body; rancidity in foodstuffs is undesirable and must be controlled.

Methods of Preventing Rancidity

The oxidation of fats and oils in food is the primary cause of rancidity. Oils/fats containing food must be kept from oxidising in order to prevent rancidity. The following methods are used to prevent or delay rancidity:

1. The use of anti-oxidants slows down the oxidation of oil or fat in food. These are the substances that have a high proclivity to oxidation. These are oxidised and thus prevent the oxidation of food materials.
2. Packing in Nitrogen: In some packed foodstuffs, such as potato chips, the plastic bags are filled with the inert gas nitrogen, preventing oxidation and rancidity.
3. Keeping in Refrigerator: This is a common method in our household. When food is stored in a refrigerator, the oxidation of fats and oils in the food is slowed due to the low temperature, reducing the rate of rancidity.
4. Storing in Air-Tight Containers: When food is stored in airtight containers, it is exposed to very little oxygen, which slows the oxidation of fats and oils in the food and thus slows the rate of rancidity.
5. Storing Foods Away from Light: When food is stored away from light, the oxidation of fats and oils in the food is slowed, and thus the rate of rancidity is slowed.
6. Vacuum Packing: In many cases, the container is evacuated before sealing after the food has been packed. This is done because there will be no air or oxygen available to oxidize food and cause it to go rancid.

Sample Questions

Question 1: What is biological oxidation?

Answer:

Biological oxidation is a biological process in which electrons are lost, as opposed to reduction, which involves the gain of electrons. Oxidation and reduction, on the other hand, are linked as a redox reaction, which is an energy-producing reaction within the cell.

Question 2: What are the effects of oxidation reactions in everyday life?

Answer:

The loss of electrons or the addition of oxygen are both involved in oxidation reactions. Many processes in our daily lives, such as respiration, combustion, and photosynthesis in plants, involve oxidation. Fats and oils oxidise and become rancid as a result of this process. That is why potato packets are filled with nitrogen gas to keep them fresh for a long time; otherwise, oxidation causes them to go rancid.

Question 3: Suggest some methods to prevent rancidity.

Answer:

Use of anti-oxidants are:

• Food packaging in nitrogen-gas flushed bags.
• Storing food in refrigerators and in air-tight containers.
• Keeping food away from sunlight.

Question 4: What are the effects of oxidation and reduction reactions?

Answer:

Any chemical reaction in which the oxidation number of a molecule, atom, or ion changes by gaining or losing an electron is an oxidation-reduction reaction. Redox reactions are common and essential to some of life’s most basic functions, such as photosynthesis, combustion, and corrosion or rusting.

Question 5: What is an example of useful oxidation?

Answer:

The combustion or burning of any substance is an oxidation reaction in which energy is always created. The combustion of various fuels is used as a source of energy in a variety of home and industrial activities.

Question 6: Write a short note on corrosion.

Answer:

Corrosion is a slow process in which the surfaces of metallic objects become coated with the metal’s oxides, hydroxide, carbonate, or sulphide. Metal is destroyed as a result of chemical or electrochemical reactions with the environment. Corrosion is also defined as the gradual deterioration of metal surfaces caused by the action of air, moisture, or a chemical on their surface. It deteriorates (damages) buildings, bridges, ships, and metal objects, particularly iron.