Titration, also known as volumetric analysis and titrimetry, is a method commonly used in chemical laboratories for quantitative chemical analysis. It is used to obtain the concentration of a specific analyte in a mixture. Some important types of titration are listed in this article.
- Analyte (commonly referred to as the Titrand) – the substance whose concentration is to be determined.
- Titrant (also known as titrator) – A reagent (of known volume and concentration) which is made to react with the analyte.
- Titration volume – the volume of titrant consumed in the titration process.
Redox titrations feature oxidation-reduction reactions between two chemical species (one of which is an oxidizing agent and the other is a reducing agent). The endpoints of these titrations are usually determined with the help of a redox indicator or a potentiometer.
Some specific redox titrations do not require any indicators (due to the powerful colour of the titration mixture). An example of such a titration is permanganometry.
These titrations feature the formation of a complex compound from the chemical reaction between the titrant and the analyte. Complexometric titrations generally require specialized indicators (commonly referred to as complexometric indicators) that have the ability to form weak complex compounds with the analyte. Examples of complexometric indicators include Eriochrome black T, Ethylene diaminetetraacetic acid (often abbreviated to EDTA), and starch indicators.
In an acid base titration, a neutralization reaction occurs between an acid and a base. Generally, a pH indicator is used to find the pH range of the endpoint of the titration. However, the actual endpoint is determined with the help of an acid-base indicator (which changes colour at the equivalence point). Some common indicators used in acid-base titrations are listed below.
- Methyl violet – turns yellow in the acidic side of the titration and violet in the basic side; the colour changes in the pH range of 0 – 1.6.
- Methyl orange – turns red in the acidic side and yellow in the basic side of titration; the colour changes in the pH range of 3.1-4.4
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