Bases That Dissolve In Water Are Called

Bases That Dissolve in Water Are Called: A Deep Dive into Arrhenius Bases

What happens when a base dissolves in water? This seemingly simple question opens the door to a fascinating world of chemistry, exploring the fundamental concepts of acids and bases. This article will explore the terminology surrounding bases that dissolve in water, delving into their properties and reactions. The short answer is that bases that dissolve in water are called Arrhenius bases. Let's explore this further.

Understanding Arrhenius Bases:

The term "Arrhenius base" is named after Svante Arrhenius, a Swedish chemist who first proposed this definition. An Arrhenius base is defined as a substance that increases the concentration of hydroxide ions (OH⁻) when dissolved in water. This increase in hydroxide ions is what leads to the characteristic properties of alkaline solutions, such as a high pH and the ability to neutralize acids.

Examples of Arrhenius Bases:

Many common household substances are Arrhenius bases. These include:

• Sodium hydroxide (NaOH): Also known as lye or caustic soda, it's a strong base used in various industrial processes and drain cleaners.
• Potassium hydroxide (KOH): Similar to NaOH, it's a strong base with applications in soap making and other chemical industries.
• Calcium hydroxide (Ca(OH)₂): Also known as slaked lime, it's used in construction, agriculture, and water treatment.
• Ammonia (NH₃): Although not directly producing hydroxide ions, ammonia reacts with water to form ammonium ions (NH₄⁺) and hydroxide ions (OH⁻), thus exhibiting basic properties. It's a weak base.

Strong vs. Weak Arrhenius Bases:

The strength of an Arrhenius base refers to its degree of dissociation in water. Strong bases completely dissociate into their ions in water, meaning all hydroxide ions are released. Examples include NaOH and KOH. Weak bases, on the other hand, only partially dissociate, meaning only a small fraction of the base molecules release hydroxide ions. Ammonia is a prime example of a weak base.

The Role of Hydroxide Ions:

The key to understanding Arrhenius bases lies in the hydroxide ion (OH⁻). This negatively charged ion is responsible for the alkaline properties of the solution. When a base dissolves in water, it releases OH⁻ ions, which then interact with other molecules and ions in the solution, leading to characteristic chemical reactions. The higher the concentration of OH⁻ ions, the stronger the base.

Beyond Arrhenius: Brønsted-Lowry and Lewis Bases:

While the Arrhenius definition is useful, it's limited. The Brønsted-Lowry and Lewis definitions provide broader perspectives on basicity. A Brønsted-Lowry base is a proton (H⁺) acceptor, while a Lewis base is an electron pair donor. While all Arrhenius bases are also Brønsted-Lowry and Lewis bases, the reverse isn't necessarily true. These broader definitions encompass a wider range of chemical species exhibiting basic characteristics.

Conclusion:

In summary, bases that dissolve in water and increase the concentration of hydroxide ions are called Arrhenius bases. Understanding this definition is crucial for comprehending fundamental acid-base chemistry and the properties of alkaline solutions. While the Arrhenius definition provides a good starting point, exploring the broader Brønsted-Lowry and Lewis definitions provides a more comprehensive understanding of the concept of basicity.