Standardization is a titration process that is used to determine the exact concentration (molarity or normality) of a prepared solution, however, not all titrations are standardization processes.
In analytical chemistry, words like standardization and titration are very significant. Although they both use the same measurement method, their applications are different from each other. Titration, generally known as the volumetric or titrimetric method, is quantitative chemical analysis. It is an analytical method for determining the concentration of a certain chemical species in a sample solution.
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A titration can be performed with a solution having a known concentration. Unlike in standardization, a solution with a known concentration is not necessarily a primary or secondary solution. Any solution with a known concentration can be used.
Titration is carried out with the use of a burette, a burette stand, and a conical flask, etc. A titrant is placed in a burette, an analyte is placed in the conical flask where the reaction occurs, and an indicator is added to cause a color change at the endpoint or equivalence point. Acid-base, redox, precipitation, and complexometric titration are the types of titration.
What is standardization in chemistry?
Standardization is a method used to determine the precise concentration of a solution. Titration is the most often used technique for standardizing a solution. A standard solution is required as a reference in the standardization process. Standard solutions are available in two types: primary standard solutions and secondary standard solutions. Generally, we use primary standard solutions for precise standardization. These solutions have a high purity (99.9% accurate) level.
The final concentration of a solution prepared from a solid chemical substance can vary depending on several factors such as the instrumental errors, purity of the compound, and human errors, etc.
For example, if you want to prepare a 1.0 molL-1 EDTA solution, you can weigh the required amount and dissolve it in a sufficient volume of water. The expected weight can be calculated using the data on the label of the bottle. However, it may not provide the exact concentration that we require. As a result, after the solution is prepared, it needs to be standardized with a primary standard solution to determine the precise concentration of the prepared solution.
Definition of standardization: The process of determining the exact concentration (molarity or normality) of a solution is known as standardization.
What is the purpose of standardization in chemistry?
Every time before starting a titration, we need to standardize the titrant. The basic purpose of standardization is to find out the precise concentration of the prepared solution.
Generally, when preparing a standard solution we do not find the accuracy in analytical terms, thus we are required to compare the values with another primary standard.
Example of standardization:
If you prepare a normal sodium hydroxide solution, you should standardize it against potassium hydrogen phthalate by using the phenolphthalein indicator. The indicator is used to produce a color change. We can't just use sodium hydroxide (NaOH) by adding it to water.
This is because NaOH is hygroscopic, which means that it absorbs moisture from the air. Hence we need to determine the exact concentration of the prepared solution of NaOH which is further used to find out the concentration of unknown sample solution by titration.
Why do we standardize a solution?
Before starting a chemical experiment, it is sometimes necessary to standardize the solution (reagents) because this will allow us to obtain accurate measurements during the experiment, even if the actual concentration of the solution varies. We can also reduce the variance of human and instrumental error by standardizing the solution.
Procedure of standardization:
- Prepare a solution that needs to be standardized
- Fill it in the burette and adjust the zero
- Weigh the required quantity of primary standard and add a sufficient volume of solvent to dissolve it.
- Add 2-3 drops of indicator
- Titrate the above solution with the titrant and note the readings
- To get accurate results, repeat the titration three times, take their mean, and calculate the molarity or normality
Frequently Asked Question (FAQ):
What is a primary standard solution and a secondary standard solution in chemistry?
A primary standard is a very pure compound used as reference material in titrations or other quantitative analysis, while a secondary standard is a compound that has had its purity determined through chemical analysis.
What is standard solution in chemistry?
In analytical chemistry, a standard solution is a solution that contains the exactly known concentration of an element. To make a specific volume, a known mass of solute is dissolved. A standard substance, such as a primary standard, is used to make it. For example, in silver nitrate (AgNO3) reactions, sodium chloride (NaCl) is used as a primary standard.
What is standard reduction potential in chemistry?
Reduction potential is also known as oxidation/reduction potential or redox potential. Standard reduction potential is the reduction potential of a molecule under specific, standard conditions.
References:
- A.I. Vogel, Text Book of Quantitative Inorganic Analysis
- Wikipedia contributors, 'Standard solution', Wikipedia, The Free Encyclopedia, 5 December 2021, 12:45 UTC, <https://en.wikipedia.org/w/index.php?title=Standard_solution&oldid=1058757605
- “What Is Standardization in Chemistry and What Is Its Importance?” Study.Com, https://study.com/academy/answer/what-is-standardization-in-chemistry-and-what-is-its-importance.html.
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