Question

Which of the following oxides can act as a reducing agent? (a) CO (b) \(\mathrm{CO}_{2}\) (c) \(\mathrm{SnO}_{2}\) (d) \(\mathrm{PbO}_{2}\)

Short answer

CO (option a) can act as a reducing agent.

Step-by-step solution

Understand the concept of a reducing agent

A reducing agent is a substance that donates electrons in a chemical reaction and gets oxidized in the process. It typically has the capacity to undergo oxidation, leading to a higher oxidation state.

Analyze each oxide to determine if it can be a reducing agent

CO can act as a reducing agent as it can be further oxidized to \(\mathrm{CO}_{2}\). CO2 is already fully oxidized and generally does not act as a reducing agent. \(\mathrm{SnO}_{2}\) and \(\mathrm{PbO}_{2}\) are oxides of metals with their highest oxidation states, and usually, oxides in their highest oxidation states do not act as reducing agents.

Choose the correct answer

Based on the above analysis, CO can act as a reducing agent, so the correct answer is option (a).

Key concepts

Oxidation States

When discussing oxidation states, we're looking at the apparent charge an atom would have if all bonds to atoms of different elements were completely ionic. This concept helps chemists understand the electron transfer process during chemical reactions.

Take carbon monoxide (CO) for instance. In this compound, carbon has an oxidation state of +2, and it has the potential to increase to +4 when it transforms into carbon dioxide (CO₂). This increase in the oxidation state from +2 to +4 signifies the loss of electrons, which is the foundational characteristic of an oxidizing agent.

The values of oxidation states guide us to predict how an atom will behave in a chemical reaction, especially if it will tend to lose or gain electrons. A solid grasp on how to determine and interpret oxidation states is crucial for understanding the roles of different substances in reactions, including identifying reducing agents.

Chemical Reactions

In the realm of chemical reactions, we encounter changes that transform one set of chemical substances to another. These reactions are driven by the movement of electrons, leading to the formation or breaking of chemical bonds.

When a substance acts as a reducing agent, it facilitates the chemical reaction by donating electrons to another species, thereby getting oxidized itself. This electron donation process alters the chemical structure and energy states of the reactant molecules, resulting in new products. The ability to identify which reactants will act as reducing agents can be predicted by their oxidation states, as we've seen with CO acting as a reducing agent by potentially oxidizing to CO₂.

An intuitive understanding of chemical reactions allows students to predict the outcome and products of reactions, which is an invaluable skill in both academic and professional chemistry environments.

Electron Donation

The term electron donation refers to the act of an atom or molecule giving up electrons during a chemical reaction. Reducing agents are quintessential electron donors. They provide the electrons that another atom or molecule requires to reduce its oxidation state.

For example, in the reaction where CO acts as a reducing agent, it donates electrons to be transformed into CO₂. This loss of electrons from the reducing agent corresponds to a gain of electrons, or reduction, of another reactant.

Understanding electron donation is crucial because it's a fundamental process that governs the mechanics behind redox reactions, including corrosion, combustion, photosynthesis, and cellular respiration. It's a central theme in chemistry that extends to many applications in life and environmental sciences.