Kimia Dasar - Redoks- Konsep Redoks

Summary

This video explains the concepts of oxidation and reduction in chemistry, contrasting the old and new theories. Oxidation is described as the loss of electrons or reactions with oxygen, while reduction involves the gain of electrons or reactions with hydrogen. The video demonstrates these concepts with practical examples, such as the reactions of CO with oxygen, Na with electrons, and Zn with HCl. It also explores redox reactions where oxidation and reduction occur simultaneously. The roles of oxidizers and reductants are clarified through real-world chemical reactions, offering viewers a comprehensive understanding of these fundamental processes.

Takeaways

• 😀 Oxidation is traditionally defined as a reaction with oxygen (O2), like the reaction of CO with O2 to form CO2.
• 😀 The new theory of oxidation states that it involves the release of electrons, such as when Na releases an electron to form Na+.
• 😀 Another definition of oxidation involves the increase in the number of oxygen atoms, for example, CO becomes CO2 by adding oxygen.
• 😀 Oxidation can also be described as the loss of negative charge, such as when fluoride (F-) loses two electrons to form F2.
• 😀 Reduction is the opposite of oxidation and involves a reaction with hydrogen, like CO reacting with H2 to form CO and H2O.
• 😀 Another definition of reduction is the decrease in the number of oxygen atoms, like CO2 reacting with carbon (C) to form CO.
• 😀 Reduction can also be described as the capture of electrons, like when K+ captures an electron to form K.
• 😀 In the case of Fe3+ reduction to Fe2+, the reduction is due to the change from +3 to +2 oxidation state.
• 😀 Reduction can also involve the addition of a negative charge, as seen when Cl2 gains two electrons to form 2Cl-.
• 😀 Oxidation and reduction processes always occur together in a redox reaction, where one substance is oxidized and the other is reduced.
• 😀 In redox reactions, the oxidizing agent gains electrons (reduced), while the reducing agent loses electrons (oxidized).

Q & A

What is oxidation according to the old theory?

In the old theory, oxidation is defined as a reaction in which a substance reacts with oxygen (O₂). An example is when carbon monoxide (CO) reacts with oxygen to form carbon dioxide (CO₂). The substance is considered to undergo oxidation due to the addition of oxygen atoms.

How does the new theory of oxidation differ from the old one?

The new theory defines oxidation as a process in which a substance loses electrons. For example, sodium (Na) releases an electron to form Na⁺, which is considered oxidation under this theory.

What is meant by oxidation through the addition of ions?

Oxidation can also be described as the addition of positive ions. For instance, in the reaction where carbon monoxide (CO) reacts with oxygen to form carbon dioxide (CO₂), the carbon undergoes an oxidation process due to the addition of positive oxygen ions.

What is the role of an oxidizer in a redox reaction?

An oxidizer is a substance that causes another substance to undergo oxidation. The oxidizer itself is reduced during the process, meaning it gains electrons.

What is reduction, and how is it related to oxidation?

Reduction is the process where a substance gains electrons. It is the opposite of oxidation, and in a redox reaction, both oxidation and reduction always occur simultaneously. When one substance is oxidized (loses electrons), another is reduced (gains electrons).

How does reduction occur through the addition of hydrogen?

Reduction can also be described as a reaction in which a substance gains hydrogen. For example, when carbon dioxide (CO₂) reacts with hydrogen (H₂), it reduces to form carbon monoxide (CO), as the carbon undergoes a reduction process by gaining hydrogen.

What is a redox reaction?

A redox reaction is a chemical reaction in which both oxidation and reduction occur simultaneously. One substance is oxidized (loses electrons), and another is reduced (gains electrons).

Can you give an example of oxidation from the provided script?

Yes, in the reaction between zinc (Zn) and hydrochloric acid (HCl), zinc is oxidized from 0 to +2 charge, meaning it loses electrons, and this is considered oxidation.

What happens to hydrogen ions (H⁺) in the reaction between zinc and hydrochloric acid?

In the same reaction, hydrogen ions (H⁺) from hydrochloric acid are reduced, meaning they gain electrons and transform from H⁺ to H₂ gas, which is a reduction process.

What is the role of a reductant in a redox reaction?

A reductant is a substance that causes another substance to undergo reduction. The reductant itself is oxidized during the process, meaning it loses electrons.