Question Video: Describing the Relationship between Oxidization and Reduction Reactions | Nagwa Question Video: Describing the Relationship between Oxidization and Reduction Reactions | Nagwa

Question Video: Describing the Relationship between Oxidization and Reduction Reactions Science • Third Year of Preparatory School

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Which of the following statements about oxidization and reduction is correct? [A] Oxidization can happen independently of reduction. [B] Reduction happens before oxidization. [C] Oxidization happens before reduction. [D] Oxidization and reduction happen concurrently.

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Video Transcript

Which of the following statements about oxidization and reduction is correct? (A) Oxidization can happen independently of reduction. (B) Reduction happens before oxidization. (C) Oxidization happens before reduction. Or (D) oxidization and reduction happen concurrently.

We can define oxidization and reduction in terms of oxygen atoms, hydrogen atoms, or electrons. Oxidization can be defined as a chemical process that increases the oxygen percentage or decreases the hydrogen percentage in a substance, whereas reduction is the opposite. It is a chemical process that decreases the oxygen percentage or increases the hydrogen percentage in a substance. In this example, hydrogen forms water when it reacts with copper oxide. When hydrogen forms water, there is an increase in the oxygen percentage. Thus, hydrogen has undergone oxidization.

For the hydrogen to receive this oxygen, the oxygen must have come from somewhere else. It has come from the copper oxide. As the copper oxide forms copper, there is a decrease in the oxygen percentage for the substance, so the copper oxide has undergone reduction. So we can see here that oxidization and reduction are happening in the same reaction.

If we look at another example, we can see that when bromine reacts with ammonia, hydrogen bromide is formed. When bromine forms hydrogen bromide, there is an increase in the hydrogen percentage. Thus, bromine has undergone reduction. For bromine to have gained this hydrogen, another chemical must have lost it. This chemical is ammonia. Ammonia loses hydrogen, forming nitrogen. So as the hydrogen percentage in the substance has decreased, we say that ammonia has undergone oxidization. So again, oxidization and reduction are happening in the same reaction.

We have now looked at the definition of oxidization and reduction in terms of oxygen and hydrogen and have seen an example in each case, where oxidization and reduction are happening at the same time. Let’s now look at the definition of oxidization and reduction in terms of electrons. Oxidization can be defined as a reaction that involves the loss of electrons from a substance, whereas reduction is the opposite. It is a reaction that involves the gain of electrons in a substance. In this example, chlorine gas reacts with sodium. When sodium reacts as a metal, it tends to form positive ions. Sodium chloride is an ionic compound. It is formed from sodium ions and chloride ions.

For neutral sodium to form positive ions, it must lose electrons from its valence shell, so sodium has undergone oxidization. When sodium loses these electrons, they are gained by chlorine, which is why chlorine goes from a neutral species to a negatively charged species. As chlorine has gained electrons, it has undergone reduction. So again, we have seen that oxidization and reduction are happening in the same reaction. We have now seen this happen for reactions where there is an increase or decrease in oxygen percentage, hydrogen percentage, or the number of electrons. We have seen that oxidization and reduction depend on each other.

For one of them to occur, the other must also occur. For oxidization to occur, reduction must occur in the same reaction, so oxidization and reduction are happening at the same time. Another word for saying at the same time is concurrently. So the statement “oxidization and reduction happen concurrently” is correct. Therefore, the answer to the question “Which of the following statements about oxidization and reduction is correct?” is (D). Oxidization and reduction happen concurrently.

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