Question

Give an example of a combination redox reaction, a decomposition redox reaction, and a displacement redox reaction.

Short answer

Examples: Combination redox - \(2H_2+O_2\rightarrow 2H_2O\), Decomposition redox - \(2H_2O_2\rightarrow 2H_2O+O_2\), Displacement redox - \(Zn+CuSO_4\rightarrow ZnSO_4+Cu\).

Step-by-step solution

Understand Redox Reactions

Redox reactions involve the transfer of electrons between two species. It stands for reduction-oxidation reactions where one substance is reduced (gains electrons) and another is oxidized (loses electrons).

Identify Combination Redox Reaction

In a combination redox reaction, two or more substances combine to form a single product, and there is a transfer of electrons involved. An example is when hydrogen gas combines with oxygen gas to form water: \[ 2H_2(g) + O_2(g) \rightarrow 2H_2O(l) \]In this reaction, hydrogen is oxidized and oxygen is reduced.

Identify Decomposition Redox Reaction

In a decomposition redox reaction, a single compound breaks down into two or more products, often with the transfer of electrons. An example is the decomposition of hydrogen peroxide:\[ 2H_2O_2(l) \rightarrow 2H_2O(l) + O_2(g) \]Here, oxygen goes through oxidation as well as reduction involving electron transfer.

Identify Displacement Redox Reaction

In a displacement redox reaction, an element in a compound is displaced by another element. A typical example is when zinc metal reacts with copper(II) sulfate:\[ Zn(s) + CuSO_4(aq) \rightarrow ZnSO_4(aq) + Cu(s) \]Zinc is oxidized to Zn²⁺, and copper is reduced to metallic copper, Cu.

Key concepts

Combination Reactions

Combination reactions are also known as synthesis reactions. In these reactions, two or more reactants combine to form a single new product. A classic example of such a reaction can be the formation of water from hydrogen and oxygen. Here, hydrogen gas ( H_2 ) and oxygen gas ( O_2 ) combine to create water ( 2H_2O ). This reaction isn't just a simple combination; it also involves a redox process:

• Hydrogen is oxidized as it loses electrons.
• Oxygen is reduced as it gains electrons.

The electron transfer between the molecules makes this reaction both a combination and a redox reaction.

Decomposition Reactions

Decomposition reactions involve breaking down a single compound into two or more distinct products. These reactions often include electron transfers, making them redox reactions as well. A common example is the breakdown of hydrogen peroxide (H_2O_2):\[ 2H_2O_2(l) \rightarrow 2H_2O(l) + O_2(g) \]In this reaction, the hydrogen peroxide breaks down into water and oxygen. Notably, this reaction includes:

• Oxygen undergoing both oxidation and reduction.
• Electrons being transferred within the decomposition process.

The simultaneous oxidation and reduction of oxygen in this process demonstrate the complexity and beauty of decomposition redox reactions.

Displacement Reactions

Displacement reactions are fascinating and involve the replacement (or displacement) of one element in a compound by another element. These reactions often reach their state through the lens of redox processes. An example is the interaction between zinc and copper(II) sulfate:\[ Zn(s) + CuSO_4(aq) \rightarrow ZnSO_4(aq) + Cu(s) \]In this reaction:

• Zinc is oxidized as it goes from Zn to Zn²⁺.
• Copper is reduced from Cu²⁺ to metallic copper.

Zinc acts as the reducing agent, losing electrons in the process and displacing copper from the compound, illustrating a perfect example of a displacement redox reaction.

Electron Transfer

Electron transfer is the hallmark of all redox reactions, essentially serving as the reaction's "engine." During any redox process, there is a movement of electrons from one reactant to another:

• A substance that loses electrons is said to be oxidized and acts as a reducing agent.
• A substance that gains electrons is said to be reduced and acts as an oxidizing agent.

This electron transfer is crucial in understanding redox reactions because it is the very definition of oxidation and reduction. Essentially, without electron transfer, redox reactions cannot occur, making it central to these chemical processes.

Oxidation-Reduction (Redox)

Oxidation-Reduction, or redox, reactions focus on the movement of electrons between substances. This paired process includes simultaneous oxidation and reduction activities. In redox:

• Oxidation refers to the loss of electrons.
• Reduction signifies the gain of electrons.

Redox reactions are essential in countless chemical processes, from the rusting of metals to the energy production in living cells. What's remarkable is how these two processes are interlinked, always occurring together and ensuring charge balance in reactions. Whether in combination, decomposition, or displacement form, recognizing the redox aspect of reactions enables a deeper understanding of chemical transformations.