Titration and Its Types

 

Titration and Its Types

Titration

Titration is an important analytical procedure carried out in laboratories to determine the concentration or strength of chemical constituents in a solution or compound.

It is a key procedure used in pharmaceutical industry to qualitatively and quantitatively analyze different raw materials and finished products.

Titration can be defined as “a process in which a solution of known concentration is used to find out the concentration of unknown solution”.  Titration is also called as Titrimetry. The solution of known concentration is termed as “Titrant” and it must be fall in category of primary or secondary standards.  Moreover the solution of unknown concentration but of known volume is termed as “Analyte or Titrate”. During titration Indicator are used that produce color changes when a chemical change occur.

Types of titration

Titration can be classified in various types depending upon the method used and the nature of solvent and chemical to be analyzed.

Classification upon the method used includes direct titration and indirect titration.

Classification based on the nature of substances includes Acid-base titration, Redox titration, Complexometric titration and Precipitation titration.

Direct Titration

Direct titration method is the most commonly used method used to carry out titration. This technique involves the reaction of unknown chemical with the known concentration chemical. The reaction between the known chemical and unknown chemical takes place directly. Hence the endpoint of titration indicates the endpoint of that reaction.

Indirect Titration

Indirect Titration is also termed as Back Titration. In Back titration the concentration of unknown chemical is determined by determining the remaining amount of the chemical of known concentration.

Back titration involves two steps, in 1^st step the reaction occur between the chemical of interest with the known amount of reactant that will be added in excess amount.

In the 2^nd step a simple titration would be carried out to find out the amount of freely available reactant that was added in excess.

Acid –Base Titration

Acid-Base Titration is also termed as neutralization titration. In neutralization or acid-base titration the concentration or strength of an acidic solution is determined by titrating it with a standard known concentration solution of base. Similarly the concentration or strength of an alkali solution of unknown strength is determined by titrating it with a standard known concentration solution of an acid.

Redox Titration

Redox Titration is based on the occurrence of oxidation-reduction reaction. In redox titration the transfer of electrons occur which lay down the bases of reaction between the reducing agent and oxidizing agent in an aqueous solution.

Redox Titrations are further divided into Permanganate Titration, Dichromate Titration and Iodometric Titrations.

Complexometric Titration

Complexometric Titration is a type of titration in which at the end point of procedure an un dissociated metal ion complex formation occurs. The complex formations takes place in between the titrant and titrate. The most common example is the titration carried out using EDTA (Ethylenediaminetetraacetic acid) that form complex with metal ions.

Precipitation Titration

Precipitation Titration is based on the formation of precipitate between the two reacting substances. The precipitate formed should be insoluble and can be clearly seen at the flask bottom. This precipitate formation is the end point.