The word ‘Redox’ is formed by combining the initials of two words; Reduction and Oxidation. Reduction is the gain of electrons and Oxidation is the loss of electrons. Such a reaction in which Reduction and Oxidation occur simultaneously is called a redox reaction. In a redox reaction, the molecule which loses electrons is oxidized while the one that gains is reduced.
Oxidation-Reduction reactions are the basis of electrochemistry. They have various laboratory and industrial applications. The charging and discharging of an electric battery is a redox reaction. Respiration, on which our life depends, is another example of a redox reaction. On an industrial level, redox reactions are used for extracting metals from their ores.
Due to their vast use case and applications, oxidation-reduction reactions hold a sacred place in chemistry. However, students are not generally excited about learning it. They find it dry and boring.
Read on to learn three reasons why Redox reactions can be tricky for students and what methods you can use to make it more interesting.
Here are three reasons why the study of redox can be a bit tricky for students:
Chemical reactions such as redox reactions are abstract for students. Since they cannot see how the interatomic bonds between the molecules break and how new bonds are formed, they don’t understand the process easily.
In their textbooks and other study materials, there are complex chemical equations to explain the reactions. This makes the topic hard for students to digest.
Chemical reactions contain multiple technical terms. It is usual for students to get confused with technical terms. For instance, they often mix up oxidation with reduction as both are based on the gain or loss of electrons. Moreover, they forget the type of redox reaction occurring at the anode and cathode of the electrochemical cell.
Chemical processes are dry and boring for students. When educators fail to mention real-world applications, students think that this content has no physical relevance. Hence, they are not interested to learn about it until you cite the related examples.
Keeping in mind the problems faced by students, here are five techniques you can use to make redox reactions an interesting topic to explore.
Stories are an interesting way to begin your lecture. When teaching something dry as redox reactions, a tale of how the concept of redox reaction evolved can be a sigh of relief for students.
The history of Redox reactions goes back to the Greeks' time. The earliest redox reaction was combustion. However, at that time, the process was based on the phlogiston theory. According to this theory, burning (oxidation) was due to the liberation of phlogiston. All other chemical reactions were based on this theory. However, it had a few flaws.
Then, in 1774, Joseph Priestley discovered oxygen and this eventually led to the end of the phlogiston theory by Antonie Lavoisier. Lavoisier provided an early definition of redox reactions. He proposed that reactions in which oxygen was consumed are oxidation reactions and reactions in which oxygen was produced are reduction reactions.
In 1897, when JJ Thomson discovered electrons, the concept of oxidation and reduction changed from loss of oxygen and gain of oxygen to gain of electrons and loss of electrons. That’s how we ended up with the modern definition of redox reactions.
When teaching abstract concepts like redox reactions, it is necessary to mention some real-life examples. Because in their minds, students ask themselves why am I studying this? Where is it used?
If you don’t relate the topic to the real world, they don’t get energized in learning about it. Second, it gives them the impression that the topic doesn’t have any notable applications. So, citing the applications is pretty important to grab their attention.
You can quote the following applications in the context of redox reactions.
Lithium Batteries in electric cars, and in our mobile phones, are the electrochemical cells, undergoing redox reactions. In electrochemical, two electrodes are dipped in an electrolyte. The charging and discharging of the battery are due to redox reactions at the anode and cathode.
A Lithium-ion battery gets its name from the lithium compound used in its electrodes. Lithium nickel manganese cobalt oxide is used in electric vehicle batteries, while in electronic devices you will see nickel cobalt oxide.
We humans breathe in and out air constantly. The process of respiration is also an example of a redox reaction. In this case, the glucose molecules are oxidized while oxygen molecules are reduced to form water.
Photosynthesis, the food-making process in plants, is another example of a redox reaction. In this chemical redox reaction, carbon dioxide is reduced to form glucose (carbohydrates) and water is oxidized to form oxygen, which is released into the atmosphere.
Metals occur in nature as ores in their oxidized forms. To extract them, we have to reduce them. For that, we need reducing agents. For instance, iron is found as Ferric Oxide, to reduce it, we use coke (carbon) as the reducing agent. This process is done at industrial in huge blast furnaces.
Since redox reaction involves two processes oxidation and reduction. Oxidation is the loss of electrons, whereas reduction is the gain of electrons. You can use explain it with an analogy of balls. Treat electrons as balls. The balls leave one molecule and get to the other one. The one which loose electrons is oxidized while the other one that gains electrons is reduced. So, with this analogy, you can easily show electron movement with metallic balls.
Figure from Labser’s simulation on Redox Reaction
Similarly, another core concept in a redox reaction is of a galvanic cell. Students have a hard time figuring out how the electrons travel through electrolytes and then get deposited at the electrode and how a battery produces current. You can explain all these things to your pupils with some colorful animations of a galvanic cell.
With animations, you can easily build an understanding of the concept in their minds. However, memorizing the technical terms can be a challenge for students. They often mix up oxidation and reduction, and anode with the cathode.
So, here are three mnemonics, you can mention to your students. This will help them in remembering some confusing terms:
Redox is the combination of two words, Reduction, and Oxidation. So, a reaction, in which oxidation and reduction both take place simultaneously is known as a redox reaction.
To distinguish between oxidation and reduction, you can remember mnemonic. OIL RIG.
OIL = Oxidation is Loss of Electrons
RIG= Reduction is Gain of Electrons
To remember which reactions occur at the electrodes of a galvanic cell, you can use this analogy:
“A” and “O” are vowels, so Anode is for Oxidation.
“C” and “R” are consonants, so Cathode is for Reduction.
In this digital era, the best way to make your lectures interesting is to use virtual lab simulations. You can simulate any chemical process on your devices and show it to students.
Here’s Labster can be of great help. At Labster, we develop interactive 3D simulations that engage students and help them learn and explore things visually. Our simulations are set up in a virtual world, where students learn things in the form of a short story. The gamified experience makes things more fun and interesting for students.
For the current case, you can check out the Labster Redox Reaction simulation, in which students discover how electric batteries. They discover the chemical reactions that power a battery and then practice some redox reactions in the virtual lab.
Find it interesting? Want to buy our simulation package for your students? Contact us now.
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