Identifying the Arrhenius Base- A Comprehensive Guide to Differentiating among Candidates

Which of the following is an Arrhenius base?

In the world of chemistry, understanding the different types of bases is crucial. One such classification is based on the Arrhenius theory, which defines bases as substances that produce hydroxide ions (OH-) when dissolved in water. This theory, proposed by Swedish chemist Svante Arrhenius in the late 19th century, provides a simple way to identify bases. However, not all bases fit neatly into this category. In this article, we will explore various substances and determine which one qualifies as an Arrhenius base.

The Arrhenius definition of a base is straightforward: it must generate hydroxide ions when it dissolves in water. This means that if a substance is an Arrhenius base, it will increase the concentration of OH- ions in the solution. Let’s examine some common substances to see if they meet this criterion.

One of the most well-known examples of an Arrhenius base is sodium hydroxide (NaOH), also known as caustic soda. When NaOH dissolves in water, it dissociates into sodium ions (Na+) and hydroxide ions (OH-). This reaction can be represented by the following equation:

NaOH (aq) → Na+ (aq) + OH- (aq)

As a result, the solution becomes basic, with a higher concentration of OH- ions. Therefore, sodium hydroxide is an Arrhenius base.

Another example is potassium hydroxide (KOH), which is also known as caustic potash. Like sodium hydroxide, potassium hydroxide dissociates into potassium ions (K+) and hydroxide ions (OH-) when dissolved in water. The reaction can be shown as:

KOH (aq) → K+ (aq) + OH- (aq)

Again, this results in an increase in the concentration of OH- ions, making potassium hydroxide an Arrhenius base.

However, not all bases are Arrhenius bases. For instance, ammonia (NH3) is a base according to the Brønsted-Lowry definition, which states that a base is a substance that accepts a proton (H+). While ammonia can act as a base in certain reactions, it does not produce hydroxide ions when dissolved in water. Therefore, ammonia is not an Arrhenius base.

In conclusion, when considering which of the following is an Arrhenius base, it is essential to look for substances that produce hydroxide ions when dissolved in water. Sodium hydroxide and potassium hydroxide are two common examples of Arrhenius bases, while ammonia is not. By understanding the Arrhenius theory and its application, chemists can better classify and study bases in various chemical reactions.