Question

Aluminium oxide is not reduced by chemical reactions since (a) Reducing agent contaminates (b) The process pollutes the environment (c) Aluminium oxide is highly stable (d) Aluminium oxide is stable

Short answer

(c) Aluminium oxide is highly stable.

Step-by-step solution

Identifying Aluminium Oxide

Aluminium oxide, often found in nature as corundum or bauxite, is chemically represented as Al₂O₃. It is a compound with aluminium and oxygen atoms and is known for its strong ionic and covalent bonds.

Understanding Stability

A compound's stability is its resistance to break down or change under different conditions, like heat or chemical reactions. Highly stable compounds often have strong bonds that require substantial energy to break.

Examining the Options

The given options mention reasons for the difficulty in reducing aluminium oxide: (a) contamination by reducing agents, (b) environmental pollution by the process, (c) high stability of the compound, and (d) general stability of the compound.

Determining the Best Explanation

Out of the given options, (c) aluminium oxide's high stability is the primary reason it is not reduced by typical chemical reactions. The energy required to break the Al-O bonds in Al₂O₃ is quite significant, making it hard to reduce using standard chemical methods.

Key concepts

Chemical Reduction

Chemical reduction is a fascinating process where a compound loses oxygen or gains electrons. This is an essential reaction in chemistry, often used to extract metals from their ores. However, the ability to reduce a compound highly depends on the compound's chemical structure and the strength of its bonds. Aluminum oxide, for example, is notoriously difficult to reduce. This difficulty arises because of the incredibly strong bonds between aluminum and oxygen atoms inside the compound. These strong Al-O bonds mean a lot of energy is needed to disrupt them.

• The process of chemical reduction involves electron transfer, typically from a reducing agent to the compound being reduced.
• The stronger the bond in a compound, the more energy is necessary for reduction, making common reducing agents ineffective.

This high energy requirement is why aluminum oxide remains stable and less susceptible to reduction under normal chemical conditions.

Aluminum Compounds

Aluminum compounds are significant substances encountered in both nature and industrial applications. One of the well-known aluminum compounds is aluminum oxide (Al₂O₃), which is found in minerals like corundum and bauxite. These compounds are prized for their hardness and are used in

• abrasives, due to their ability to resist scratching,
• industrial applications, such as the production of aluminum metal,
• ceramics, due to their thermal resistance.

What makes aluminum compounds particularly interesting is their ability to form various kinds of bonds, both ionic and covalent, depending on the context and compounds involved. This combination of bond types contributes to the overall stability of the compound, making them less reactive and more robust under many conditions.

Chemical Bond Stability

Chemical bond stability is a fundamental concept that dictates how resistant a compound is to changes, such as those induced by heat or chemical reactions. In aluminum oxide, bond stability plays a crucial role. The combination of strong ionic and covalent bonds between aluminum and oxygen in Al₂O₃ results in high bond stability.

• Bond stability is determined by the energy required to break the bond.
• Typically, the stronger the bond, the more stable the compound.
• Stable compounds like aluminum oxide resist reactions that would traditionally break them down.

Understanding bond stability helps explain why some compounds, like aluminum oxide, remain stable even when subjected to potentially reactive environments. This is key in industries where maintaining material integrity is critical.