Titration
The method by which a solution of a certain concentration is added to another solution to complete the chemical reaction between two solutes is called titration.
Introduction
Titration is one of the methods of volumetric analysis. In volumetric analysis, the body is first dissolved and a certain volume of solution is measured with another solution whose concentration is known, which is called the standard solution. In titration, the standard solution is slowly added from a burette to a solution containing a specified volume or weight of solute.
The standard solution is continued to increase until its value is equal to the value of the dissolved object. Equivalent point is the point at which the amount of standard solution added is chemically equal to the amount of volume required in the unknown solution. This point is also called the end point of action in theory or equivalence point.
How to headline
In the titration operation, the standard solution is added from a port to the solution at which the concentration is to be measured, and this operation continues until the chemical reaction between the standard solution and the titrant is complete. Then, using the volume and concentration of the standard solution and the volume of the titrating solution, the concentration of the titrating solution is calculated.
Types of headlines
Volumetric analyzes (titration) are divided into two categories according to the reactions that take place between the titrant and the standard solution:
Methods based on the composition of ions. That is, there is no change in capacity in related interactions. These methods include:
1. Neutralizing reactions or reactions acid And open
2. Sedimentary reactions
3. Reactions that produce complex compounds.
Methods based on electron transfer; Such as oxidation and reduction reactions
Titrate acid reactions and open or neutralize
Titration is the determination of the amount of acid or base in a solution by gradually increasing one base to a specific concentration or vice versa. When the solution has an ionic base –OH Is added to the acid solution, the neutralization reaction is performed:
OH- + H3O+ —–> 2H2O
Classification of titration reactions
- Open acid titrations include:
- Strong acid and base
- Weak acid with strong base
- Weak base with strong acid
- Poor acid and base
- Sedimentary titrations include:
- Titration with inorganic titrants
- Surfactant titrations
- Oxidation and reduction titrations (redox)
- Complexometric / kylometric titrations
Equivalent point detection methods
Equivalent point is known in practice by physical change (for example, color change). The point at which this color change occurs is the end point of the headline. In acid titration and re-detectors are used to determine the time to reach the equinox point. The color change of the reagent indicates the end point of the titration.
Basically, the equilibrium point is reached when the titrant analyte reacts completely with the corresponding stoichiometric ratio.
If we think of titration as “counting ions or molecules”, it must be very important to get the equivalence point.
This can be done by using the properties of some solutions as a color detector that at best change color at the equivalence point.
But this color change occurs at the end point, not at the equilibrium point, although the end point is very close to the equilibrium point. But we will always have errors in this method of propagation. Besides, the recognition of different people in color recognition is very different.
Applications of neutralization titrations
Neutralization titrations are used to measure countless mineral, organic, and biological species that have intrinsic acidic or alkaline properties. But there are many applications of equal importance in which the analyte is converted to an acid or base with a suitable reagent and then titrated with a standard base or strong acid.
Two major types of endpoints are widely used in neutralization titrations. The first type is a visual endpoint and is based on the color change of the detector. The second type is a potentiometric endpoint in which the potential of a glass-chamber electrode system is determined by a voltage measuring device. The measured potential is directly proportional to PH Is.
Elemental analysis
A number of important elements that are involved in organic and biological systems can be easily measured by methods that ultimately lead to an acid-base titration. Elements that are capable of this type of decomposition are generally non-metallic and include carbon, nitrogen, sulfur, chlorine, bromine, fluorine, and several other uncommon species. In each case, the element is converted to an acid or mineral base and subsequently titrated.
For example, nitrogen is found in many important materials in research, industry, and agriculture. For example, nitrogen is found in amino acids, proteins, synthetic drugs, chemical fertilizers, explosives, soil, drinking water, and dyes. Therefore, decomposition methods are very important for determining nitrogen, especially in organic matter.
Mineral measurement
Many mineral species can be measured by titration with strong acids or bases. For example, ammonium salts can be measured simply by converting to ammonia by a strong base and then distilling in a caldera. Ammonia is collected and titrated according to the Keldal method. The method described for ammonium salts can be generalized to measure nitrate and mineral nitrite.
Determination of organic functional groups
Neutralization titrations provide simple methods for the direct and indirect measurement of a variety of organic functional groups.