Ionization of a compound in Chemistry is the process by which neutral molecules are divided into charged ions in a solution. According to the Arrhenius Theory, acids are substances that dissociate in an aqueous medium to produce hydrogen ions, H⁺ ions, and bases are substances that dissociate in an aqueous medium producing OH^– ions. The strength of acids and bases can be defined based on the degree of ionization of acids and bases.

Here in this article, we will learn about, Ionization Definition, Arrhenius Concept of Acid and Base, and Explanation of Arrhenius Acid and Base Ionization concept, Examples, and others in detail.

What is Ionization?

Ionization of a compound is defined as the process in which a compounds dissociates into its constituent ions. When a compound whether acidic or basic is dissolved into an aqueous solution, they dissociate into positive and negative ion respectively. In case of acids, the H+ ions are release and in case of base OH- ions are released. Sometimes, the ionization is not easy such as in salts. The compounds that is to be dissolved in the given solvent is called the electrolyte and its dissociation is measured in form of degree of dissociation.

Degree of Ionization

Degree of Ionization of any compound is defined as the ratio of the number of molecule undergoing dissociation to total number of molecules of the compound. It is defined using the symbol “α”(Degree of Ionization)

Arrhenius Concept of Acid and Base Ionization

Arrhenius explain the concept of acid and base as the compounds that in aqueous medium generates ions. “An acid is a compound that produces an Hydrogen Ions(H⁺) in the aqueous solution” whereas “Base is a compouns that produces Hydoxyl Ions(OH^–) in the aqueous medium.”

Ionization of Acid(HCl)

HCl(aq.) → H⁺ + Cl^–

Ionization of Base(KOH)

KOH(aq.) → K⁺ + OH^–

Explanation of Arrhenius Acid and Base Ionization

Accoring to Arrhenius, the dissociation equillibrium of acid and base are dynamic in nature. Suppose we take an acid HA and HA has higher tendency to donate eclectrons than H3O⁺ then in that case HA acts as strong acid.

HA + H₂O ⇌ H₃O⁺ + A^–

Now, stronger acid denotes protons the equlibrium moves in the direction of formation weaker base. This implies that a strong acid generally have a weaker base.

Ionization of Acid and Base

Degree of ionisation of the acids and bases contributes to their strength. The degree of ionisation might vary depending on the acidic and basic substances. Ionization constant of acid and base is the constant that tells us the strength of acid and the base. Higher the dissociation constant of acid and base higher is the strength of acid and base.

Ionization of Acids

Degree of ionisation refers to the acidity or baseness of an acid or base. A strong acid ionizes completely in the water, whereas a weak acid just ionizes partially in the aqueous solution. Now an Arrhenius Acid ionizes as,

HA (aq) + H₂O ⇌ H₃O⁺ (aq) + A^–

Now, the equllibrium constant is,

K_a = [H₃O⁺] [A^–] / [HA]

where K_a is the ionization constant of acid and hiher the value of K_a higher is the strength of the acid.

Ionization of Bases

In an aqueous solution, some bases, such as Lithium Hydroxide or Sodium Hydroxide, totally dissociate into their ions and are referred to as strong bases. Now an Arrhenius Base ionizes as,

A + H₂O ⇌ OH^– + HA⁺

Now, the equllibrium constant is,

K_b = [OH^–] [HA⁺] / [A]

where K_b is the base ionization constant and higher value of K_b represent the higher strength of the base.

Acid and Base Ionization Example

Ionization of various acid and bases are added below,

Ionization of Acid

The ionization of some popular acids are discussed below:

HCl (Hydrochloric Acid) is a strong acid and it ionizes as,

HCl + H₂O ⇌ Cl^– + H₃O⁺

CH₃COOH (Acetic Acid) is a weak acid and it ionizes as,

CH₃COOH + H₂O ⇌ CH₃COO^‾ + H₃O⁺

Ionization of Base

The ionization of some popular bases are discussed below:

NaOH (Sodim Hydroxide) is a strong base and it ionizes as,

NaOH + H₂O ⇌ Na⁺ + OH^–

NH4OH (Ammonium Hydroxide) is a weak base and it ionizes as,

NH₃ + H₂O ⇌ NH₄⁺ (aq) + OH^‾(aq)

Read More,

• Acid, Base and Salt
• Strong and Weak Base
• Chemical Indicators

Acid and Base Ionization – FAQs

1. What are Acids and Bases?

Acids are the compounds that release H⁺ ion in aqueous solution and have a highly sour flavour. Orange juice and lemon juice are two examples of acids. Bases he compounds that release OH^– ion in aqueous solution have a more harsh flavour. As an example of a base, consider soap (made of magnesium hydroxide or potassium salts).

2. What does Ionization of Base mean?

In an aqueous media known as a strong base, some bases, such as lithium hydroxide and sodium hydroxide, are totally dissociated into ions. As a result, the ionisation of these bases results in the formation of hydrogen chloride ions, such as (OH^–).

3. What does Ionization of Acid mean?

The degree of ionisation is determined by the acid or base strength. Strong acids are totally ionised in water, whereas weak acids are just partially ionised. Because the degree of acid ionisation varies, so does the degree of weakening.

4. How to know if Something Ionizes Completely?

Degree of disassociation of any compound tells us the percent of the ionization of that compound. So if the degree of ionization of any compound is 1 it tells us that the compound ionizes completely.

5. What is Percent Ionization Formula?

Percent ionization formula of weak acid or weak base is,

Percent Ionization = (Concentration of Ionized Weak Acid Or Base)/(Initial Concentration of Acid or Base) × 100

6. Does the Ionization of an Acid or Base Increase with Dilution?

Ionization of weak electrolytes, i.e. Acids or Bases increases with the increases in the dilution of the solution.

7. What happens when a Base reacts with an Acid?

When a base reacts with an acid neutralization rections occurs. In this reaction acid neutralizes base and salt and water is formed. For example a neutralization reaction is,

HCl + NaOH ⇌ NaCl + H₂O