Question

Does an oxidizing agent increase or decrease its own oxidation state when it acts on another atom? Does a reducing agent increase or decrease its own oxidation state when it acts on another substance?

Short answer

An oxidizing agent decreases its own oxidation state when it acts on another atom, as it is reduced and gains electrons. Conversely, a reducing agent increases its own oxidation state when it acts on another substance, as it is oxidized and loses electrons.

Step-by-step solution

Understand Oxidation and Reduction

Oxidation is a process where a substance loses electrons, leading to an increase in its oxidation state. On the other hand, reduction is a process where a substance gains electrons, resulting in a decrease in its oxidation state.

Understand the role of Oxidizing and Reducing Agents

An oxidizing agent is a substance that has the ability to oxidize other substances (i.e., cause them to lose electrons) and is reduced in the process. A reducing agent, on the other hand, has the ability to reduce other substances (i.e., cause them to gain electrons) and is oxidized in the process.

Determine the effect of an Oxidizing Agent on its own Oxidation State

Since an oxidizing agent is reduced during a redox (reduction-oxidation) reaction, it gains electrons and hence, decreases in its own oxidation state. This is because a decrease in oxidation state is associated with a gain in electrons.

Determine the effect of a Reducing Agent on its own Oxidation State

On the other hand, a reducing agent is oxidized during a redox reaction, meaning it loses electrons, leading to an increase in its own oxidation state. This is because an increase in oxidation state is associated with a loss of electrons. In conclusion, an oxidizing agent decreases its own oxidation state when it acts on another atom, while a reducing agent increases its own oxidation state when it acts on another substance.

Key concepts

Oxidation and Reduction

Understanding the fundamental concepts of oxidation and reduction is crucial in the study of redox reactions. Oxidation is the process by which a substance loses electrons. This is often accompanied by an increase in oxidation state and can be thought of as the substance becoming more 'electron-deficient'. In contrast, reduction involves the gain of electrons, which leads to a decrease in the oxidation state of the substance, making it more 'electron-rich'.

It's helpful to remember the mnemonic 'LEO the lion says GER': Loss of Electrons is Oxidation, and Gain of Electrons is Reduction. Redox reactions are essential in various biological and chemical processes, such as cellular respiration and corrosion.

Oxidizing Agent

An oxidizing agent, also known as an oxidant, is a substance with the ability to accept electrons from another substance during a chemical reaction. In other words, it 'oxidizes' another substance. By accepting electrons, the oxidizing agent undergoes reduction itself, leading to a decrease in its oxidation state.

This concept might seem counterintuitive at first glance; however, it becomes clearer when you think of the oxidizing agent as the substance that causes another to lose electrons while it gains them. Common examples of oxidizing agents include oxygen, chlorine, and hydrogen peroxide.

Reducing Agent

A reducing agent, sometimes called a reductant, acts opposite to an oxidizing agent. It donates electrons to another substance and is thereby oxidized in the process. Its own oxidation state increases as electrons are removed from it, effectively undergoing 'oxidation'.

During its action, the reducing agent transfers electrons to the substance that is being reduced, thereby facilitating that substance's reduction. Substances that serve as strong reducing agents have a high tendency to lose electrons. Examples include metals such as sodium, iron, and aluminum.

Electron Transfer

At the heart of redox reactions lies the transfer of electrons between substances. This electron transfer is what drives the oxidation and reduction events. In a redox reaction, there is always a pair of processes: one substance loses electrons (oxidation) while another gains electrons (reduction).

The substance donating electrons is the reducing agent, and the substance accepting electrons is the oxidizing agent. It's this flow of electrons that determines the direction and spontaneity of the redox reaction. Understanding electron transfer helps in visualizing how energy can be stored or released during chemical reactions.

Oxidation States

The concept of oxidation states, or oxidation numbers, is a way to keep 'account' of the electrons during a redox reaction. Oxidation states are assigned to atoms depending on the presumed ionic charge that atom would have if the compound was entirely ionic. This is a theoretical construct that can help predict the movement of electrons.

An increase in oxidation state corresponds to oxidation, whereas a decrease corresponds to reduction. For instance, in the oxidation of Fe(II) to Fe(III), iron's oxidation state increases from +2 to +3, indicating it has lost an electron. Oxidation states provide a useful way to analyze complex reactions, by clearly identifying which atoms are oxidized and which are reduced.