Types of Oxidation-Reduction Titrations

Redox indicators are oxidants or reductants in and of themselves. The reduced form has one colour, and the oxidised form has another. When there is an excessive amount of oxidant present. The indicator changes colour and is displayed as the titration’s finish point. The reduction and oxidation reactions that arise between the titrant and the titrate are studied using redox titration. You must understand everything about redox titrations and acid-base titrations used in diverse sectors, unlike precipitation and acid-base titrations. A comprehensive explanation follows. Let us understand the redox titration definition in detail!

What is redox titration? Explain with an example?

Oxidation-reduction titration is a type of redox titration. It is an oxidation-reduction reaction involving an oxidising and a reducing substance. In this type of titration, electrons are transferred to the reactant ions of aqueous solutions, causing a chemical reaction.

An oxidising chemical is titrated with a standard solution of a reducing agent, or a reducing compound is titrated with a standard oxidising agent in the oxidation-reduction titration procedure.

It is used to look for organic solutes and assess chlorination. In oxidation-reduction (redox) titration, a specific redox indicator solution can help.

The most frequent example of redox titration is treating an iodine solution with a reducing agent to create iodide while employing a starch indicator to help determine the titration’s endpoint.

Importance of Redox Reaction

Electrolysis, based on redox processes, is also used to make certain vital compounds. Redox reactions make several compounds, such as caustic soda and chlorine.

 The oxidation-reduction reactions are also used to sanitise water.

Many metal surfaces can be protected from corrosion by connecting them to sacrificial anodes, which corrode instead of the metal. Galvanization of steel is a typical example of this method.

• The oxidation process is used in the industrial manufacturing of cleaning goods.
• The oxidation reaction of ammonia produces nitric acid, which is used in many fertilisers.
• Electroplating is applying a thin layer of material to an object using redox processes. Gold-plated jewellery is manufactured via electroplating.
• Redox reactions are used to extract several metals from their ores. Smelting metal sulphides in the presence of reducing chemicals are one example.

Types of Redox Titrations

Redox titration is done in practice by quantitatively examining the reaction between oxidising and reducing chemicals. As a result, redox titration is classified as oxidimetry or reduximetry, depending on the composition of the standard solution. Here is how it works.

1. Permanganometry

This form of redox titration efficiently uses KMnO4 as the titrant and oxidizer, as the name implies. You can use an acid such as dilute H2SO4 or HClO4 for permanganometry; however, Cl- is prone to oxidation and has poor stability. Permanganometric titration does not require an indicator when using a colourless solution because a drop of 0.1 N permanganate in 100 ml of solution shows a purplish-pink colour.

2. Dichromatometry

Dichromatometry uses dichromate (Cr2O72-), a potent oxidising agent that is permanganate-free. The dichromate ion is reduced to Cr3+, which has a green tint during the process. Dichromate is used due to its high stability and purity; however, it has a slow response rate.

3. Iodometry and iodimetry

Iodometric and iodometric titrations are iodine-based redox titrations. Iodometry uses iodine as a reducing agent and a thiosulfate solution to titrate the released iodine. Meanwhile, iodimetry is a direct titration that uses iodine as an oxidising agent and is performed at a neutral or slightly acidic pH.

4. Bromatometry

The reducing agent and titrant in bromometry is potassium bromate (KBrO3). Bromatometry is frequently performed in hot temperatures and acidic pH settings to speed up the reaction. Excess KBr causes a reaction with the bromate ion, resulting in a faint yellow tint that is difficult to identify as an endpoint.

5. Cerimetric titration:

Cerimetry is a volumetric chemical analysis method that can examine nonstoichiometric levels that oxidise or decrease Fe3+. A colour change in the iron (II)–1, 10-phenanthroline complex determines the endpoint of this form of redox titration (ferroin).

Redox Titration Examples

A redox titration, for example, can be set up by forming iodide from an iodine solution using a reducing agent. A starch solution can be employed as a colour-change indicator to identify the titration endpoint. When all of the iodine has been reacted, the solution turns blue and disappears at the conclusion.

Conclusion

A redox titration occurs when an oxidising agent titrates a reducing agent, or a reducing agent titrates an oxidising agent. A redox indicator or a potentiometer is usually used in this form of titration. The form of the matching titration curve must be obtained in order to evaluate redox titrations. It is more convenient to measure the reaction potential rather than the concentration of a responding species in these types of titrations.