Principle, types and application of acid-base titration

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Principle, Types And Application Of Acid-Base Titration:

In laboratories, titration is used to determine the concentration of a specific analyte through quantitative chemical analysis.

It is done by adding the titrant from a burette until the reaction is complete, and an indicator is typically used to mark the point where the reaction is complete. Titrimetry is also known as volumetric analysis.

In quantitative chemical analysis, acid-base titrations and redox titrations are the two types of titration commonly used, although different types of titration exist, such as precipitation and complexometric titrations.

What is acid-base titration and understand with an example?

In an acid-base titration, a standard solution is precisely neutralized with an acid or base to determine the concentration of the solution, and a pH indicator is used to monitor the reaction.

When the acid dissociation constant (pKa) of an acid or the base dissociation constant (pKb) of a base is known, the concentration (molarity) of the analyte solution can be determined.

By generating a titration curve for a known concentration of the solute solution, the pKa can be calculated.

What is the Principle of Acid-base titration?

According to the theory of acid-base titration, a burette and pipette along with a pH indicator are used along with a burette and pipette to measure the concentration of acid or base.

During titration, a neutralization reaction usually occurs between acid and base, hydroxide ions and hydrogen protons, resulting in the formation of water.

An indicator dye is a substance added to a solution to cause its color to change, which is affected by the pH of the solution.

As a result of its dissolution in the sample solution, it is often used to determine the titration endpoint, also known as the equivalence point, at which the color changes.

What are the indicators used in acid-base titration?

An indicator’s pH range is determined by the acid strength of the indicator, which is its most important property. A pH indicator’s pH range is the range of pH values within which the indicator’s color changes from acid to base.

Only the acid form of the solution is visible at the lowest pH, while only the base form of the solution can be seen at the highest pH. It is not sensitive to pH changes outside of its range because the indicator does not change color at certain pH levels.

Indicators of acidity and base are generally grouped into the following three categories:

  • Phthalein and sulphophthalein: for example, phenolphthalein indicator
  • Azo indicators: for example, methyl orange
  • Triphenylmethane indicators: for example, malachite green

Indicators to be used in acid-base titration:

There are different indicators used in acid-base titrations. It is important to select indicators that have a pH range within the change in pH of the reaction and are suitable for the type of titration being performed.

  • Strong acid-strong base: Phenolphthalein is preferable due to the color change that is more noticeable.
  • Weak acid-strong base: Phenolphthalein seems to be a better option for this titration since it changes rapidly at the equivalence point.
  • Strong acid-strong base: Methyl orange is preferred because its equivalence point changes dramatically at this point.
  • Weak acid-weak base: Indicator is not suitable for this titration as a vertical portion of the curve is required above two pH units.

Types of Acid-base titrations with examples:

There are four types of acid-base titrations, including strong acid-strong base, weak acid-strong base, strong acid-weak base, and weak acid-weak base.

Strong acid-strong base:

Among the four different types of acid-base titration, it is one of the easiest to perform experimentally.

This reaction results from the dissociation of a strong acid and a strong base in water, resulting in the neutralization of both acids and bases. A solution that contains the same moles of acid and base and has a pH of 07.00 is said to have reached the equivalence point.

Weak acid-strong base:

Titrations of this type result in direct proton transfer from the weak acid to the hydroxide ion. As soon as a weak acid (acetic acid) interacts with a strong base (NaOH), the two react on a one-to-one basis.

A weak acid–strong base titration exhibits a pH level above 07.00 when it reaches equivalence.

Strong acid-weak base:

As a result of this type of titration, acid and base will react, producing an acidic solution. The titration results in the formation of a conjugate acid, which, when combined with water, forms hydronium ions. Titrations with weak acids and strong bases converge on a pH below 07.00 at its equivalence point.

Weak acid-weak base:

Unlike strong acids and strong bases, weak acids and strong bases have titration curves that are highly influenced by both the acid’s identity and the base’s ionization constant (Kb).

Similarly, the pH changes more slowly for weak acids or bases around equivalence points, which are greater or lower than 07.00, respectively.

Some examples are:

  1. Strong acids include hydrochloric acid (HCl) and sulphuric acid (H2SO4).
  2. Weak acids include acetic acid (CH3COOH) and formic acid (CH2O2).
  3. Strong bases include sodium hydroxide (NaOH) and potassium hydroxide (KOH).
  4. Weak bases include ammonia and methylamine.

Applications of Acid-Base Titration:

  • The most common application of acid-base titrations is determining an unknown analyte’s acid or base concentration.
  • Quantitative chemical analysis is carried out with it.
  • Pharmaceutical applications are possible with this compound.
  • An environmental analysis can be conducted with it.
  • A barbiturate, aspirin, and amino acid are determined using it.

Frequently Ask Question (FAQ):

1. What is the importance of acid-base titration?

The goal of a strong acid-base titration is to determine the concentration of an acid solution by titrating it against a known concentration of a basic solution, or vice versa until neutralization is achieved.

2. In acid-base titrations, which indicator is used?

There are a number of indicators that are used in an acid-base titration, including Phenolphthalein, Thymol Blue, Methyl Orange, Methyl Yellow, Methyl Red, etc.

3. In acid-base titrations, why is phenolphthalein used?

In An indicator that changes color in a pH range between 8.3 and 10 is used in a strong acid-strong base titration.

4. Which of the following three theories describes acids and bases?

A single characteristic that identifies an acid or base is described by three theories: the Arrhenius concept, Bronsted-Lowry concept, and Lewis concept.

Here we understood the what is the principle, types and application of Acid-Base titration in pharmaceuticals?

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