Which of these is a chemical property of aluminum? Aluminum has a density of 2.70 g · cm−3 Aluminum is silvery white in color. Aluminum is highly reactive. Aluminum is a soft metal.
The Correct Answer and Explanation is :
The correct answer is: Aluminum is highly reactive.
Explanation:
A chemical property refers to a characteristic that describes how a substance interacts with other substances to undergo a chemical change, forming new substances in the process. It involves the substance’s ability to react chemically under certain conditions. The reactivity of aluminum is a chemical property because it describes how aluminum interacts with other elements or compounds.
Aluminum is highly reactive, particularly when exposed to air or water. However, its reactivity is not immediately apparent due to the formation of a thin, protective oxide layer (Al₂O₃) on its surface. This oxide layer forms when aluminum reacts with oxygen in the air, and it serves to protect the underlying metal from further corrosion. Despite this protective layer, aluminum can react with substances such as acids and bases. For example, aluminum reacts with hydrochloric acid (HCl) to produce hydrogen gas (H₂) and aluminum chloride (AlCl₃), showcasing its reactivity in certain conditions.
The other options listed are physical properties of aluminum:
- Aluminum has a density of 2.70 g · cm−3: Density is a physical property because it relates to the mass and volume of the substance without changing its chemical composition.
- Aluminum is silvery white in color: Color is another physical property, as it can be observed without altering the chemical structure of the substance.
- Aluminum is a soft metal: Hardness or softness refers to how easily a material can be deformed, which is a physical property. The softness of aluminum is due to its relatively low strength compared to other metals.
Thus, the high reactivity of aluminum is the only chemical property among the choices, as it involves the potential for aluminum to undergo chemical transformations in specific environments.