Monobasic and Polybasic Acids

Strong acids and weak acids are the two main types of acids. Strong acids are more potent than weak acids. Acids can also be divided into three groups: monobasic acids, dibasic acids, and tribasic acids. Monobasic acids are the most common type of acid. Acids are classified in this way based on the number of protons they contain, which is necessary for them to react with a base. Polybasic acids are formed by the combination of dibasic and tribasic acids. These monobasic and polybasic acids can be either strong or weak acids, depending on their molecular structure. While there are some similarities between monobasic acids and their dibasic counterparts, the most significant distinction is that a monobasic acid has only one replaceable hydrogen atom, while a dibasic acid has two replaceable hydrogen atoms, and a tribasic acid has three replaceable hydrogen atoms.

What are Monobasic Acids and How Do They Work?

When it comes to acids, monobasic acids are acidic compounds that contain only one replaceable hydrogen atom per acid molecule. These acids have the ability to remove one proton from an aqueous solution (a hydrogen atom). As a result, they are referred to as monoprotic acids. When a monobasic acid reacts with a base, it can only donate one hydrogen atom, which is known as the hydrogen donor limit.

Given that a monobasic acid dissociates into a single hydrogen atom, the equation for the dissociation constant of a monobasic acid only includes the concentration of a single H+ ion in the equation. The dissociation of a monobasic acid is illustrated in the diagram below.

An example of this is HA(aq) → H+(aq) + A– (aq)

or

When you combine HA(aq) and H2O(l), you get A–(aq) + H3O+ (aq)

Ka is the dissociation constant and is equal to [H+(aq)].

The most significant distinction is between monobasic dibasic and tribasic acids.

Monobasic acids are found in both organic and inorganic forms. Some acids are very strong, whereas others are very weak acids. When combined with a base, strong monobasic acids like HCl, HNO3, HBr can completely dissociate and donate one hydrogen to it. Weak monobasic acids, such as acetic acid (CH3COOH), are dissociated to a significant extent.

What are Dibasic Acids and How Do They Work?

Dibasic acids are chemical compounds that contain two hydrogen atoms that can be replaced in each acid molecule. As a result, these dibasic acids can contribute two hydrogen atoms to the reaction between a dibasic acid and a base when used in this manner. Diffusion of dibasic acids into aqueous solution results in the formation of two hydrogen ions (H+) in the system. As a result, these acids are referred to as diprotic acids.

The dissociation constant of a dibasic acid can be calculated as follows. A dibasic acid has two different values for its dissociation constant. Both the first dissociation and the second dissociation are addressed in this section.

The reaction H2B(aq) = 2H+(aq) + B-2 is a two-step reaction (aq)

or

H2B(aq) = H+(aq) + HB–(aq); Ka1 = H+(aq) + HB–(aq);

HB–(aq) = H+(aq) + B-2(aq); Ka2 = H+(aq) + B-2(aq);

Ka1 is the dissociation constant and it equals [H+(aq)].

Phosphoric acid is a common inorganic tribasic acid that occurs naturally (H3PO4). It is made up of three hydrogen atoms that are bonded to three oxygen atoms that are arranged around a phosphorus atom. These hydrogen atoms in the molecule can either be replaced or removed from the structure. Citric acid is a tribasic acid that is found in many organic compounds.

The differences between monobasic, dibasic, and tribasic acids

One Replaceable Hydrogen Atom Per Acid Molecule: Monobasic acids are acidic compounds that contain one replaceable hydrogen atom per acid molecule.

Dibasic Acid: Dibasic acids are chemical compounds that contain two hydrogen atoms that can be replaced by other hydrogen atoms in each acid molecule.

Chemical compounds that contain three replaceable hydrogen atoms per acid molecule are known as tribasic acids .

The donation of hydrogen ions for acid-base reactions

Monobasic Acid: In an acid-base reaction, monobasic acids can only donate one hydrogen ion, so they are called monobasic acids.

The acid-base reaction can be aided by the use of dibasic acids, which can donate two hydrogen ions.

Three hydrogen ions can be donated by tribasic acids in an acid-base reaction, making them useful in acid-base reactions.

Dissociation

Monobasic Acid: Monobasic acids do not dissociate in a stepwise fashion.

Dibasic Acid: The dissociation of dibasic acids occurs in two stages.

Tribasic Acid: The dissociation of tribasic acids occurs in three stages.

Conclusion

Acids are substances that have the ability to release protons (or H+ ions) into a system. As a result, the presence of an acid is indicated by a low pH value in the system in question. It is dependent on the type of acid present in a system to determine the acidity of that system. Acids are primarily divided into two categories: strong acids and weak acids. Acids can be classified into two types: monobasic acids and polybasic acids, which are distinguished by the number of protons that they donate to an acid-base reaction during the reaction. Polybasic acids are dibasic acids and tribasic acids, respectively. As previously stated, the primary difference between monobasic acids and dibasic acids and tribasic acids is that a monobasic acid contains only one replaceable hydrogen atom, whereas dibasic acids contain two replaceable hydrogen atoms and tribasic acids contain three replaceable hydrogen atoms.