The term titrant is used in the titrimetric analysis. The titrant is a reagent of known concentration. It is used for standardization. As the concentration of titrant is known, it is also known as a standard solution. It is added to the solution of an unknown concentration, with a suitable indicator, to find out the concentration.
During titration, titration flask is filled with the known solution whose concentration is to be found. The titrant is filled in burette. It is slowly added into the titration flask with constant stirring. A few drops of a suitable indicator must be added into the titration solution before the addition of the titrant.
Now, the addition of titrant results in the ionization of the indicator which leads to the color change. A permanent color change is the endpoint of the titration. At the end point reaction is completed. This process is repeated 3-5 times and results are used for the calculation of the concentration of that solution.
Calculation of concentration
Formula:
C1V1=C2V2
where,
- C1= concentration of titrant
- C2=C1V1 / V2 V1= used volume of titrant
- C2= unknown concentration of analyte
- V2= known volume of analyte
For example
C1= 0.1 M (titrant)
C2= ?
V1=10 ml (volume used)
V2= 20 ml (analyte)
By putting values in above give formula
C2=C1V1 /V2
C2=0.1×10 /20
C2=0.05M
Preparation of titrant (Standard Solution)
If reagent is available in pure state, a solution of desired molarity is prepared by dissolving required quantity into suitable solvent. Commonly used solvent is water.
It is more convenient to prepare solution little concentrated than required and then diluting it with water until desired molar strength is obtained.
The following substance are available in highly pure form and are suitable for standard solution: Sodium oxalate, silver nitrate, potassium hydrogenphthalte, sodium tetraborate, sodium carbonate, iodine, potassium chloride, lead nitrate, potassium iodate, arsenic (III) oxide, etc.
When the reagents are not available in pure form, then the titrants are standradized by titration against solution of pure substances of known concentration. This process is commonly used in case of alkali hydroxides, in some organic acids, and various deliquescent substances. For example, NaOH, KOH, BaOH, KMnO4, sodium thiosulfate (Na2S2O3) etc.
Commonly used titrants
Here are some of the most commonly used titrants:
- HCl, NaOH (acid base titration)
- Silver nitrate (precipitation titration)
- EDTA, ZnSO4 (complexometric titration)
- KMnO4,K2Cr2O7 (redox titration)
- Per Chloric acid (non aqeous titration)
- I2 (idometric titrations)
Characteristic of good titrant
- It should be of high purity.
- It should be of known concentration.
- It must be stable (non-reactive toward air)
- It should be easily available.
- It should specifically react with analyte.
- It does not require standardization.
Related Resouces:
Concepts berg
Define titration.
Titration is a type of volumetric analysis which is used to find out the unknown concentration of known analyte by using suitable indicator and standard solution (titrant).
What are different types of titration?
The types of titrations are:
- Acid base titration
- Redox titration
- Complexometric titration
- Precipitation titration
- Non aqueous titration
- Back titration
- Amperometric titration
- Potentiometric titration
- Zeta potential titration
- Spectrophotometric titrations
Define titrant.
Titrant is solution of known concentration and is used to findout concentration of analye in the presence of suitable indicator. Titrant is also known as standard solution.
Define titrand.
Titrand is solution of unknown concentration and known volume. It is also named as anlayte. Its concentration is find out by titrating it against standard solution.
What is meant by primary standard?
Primary standard is compound of high purity and that is used as reference material in a different type of analysis.
What are the example of titrant?
- HCl
- NaOH
- ZnSO4
- EDTA
- KMnO4
- Perchloric acids
- Iodine solution
- Sodium thiosulfate
- Silver nitrate solution
- K2Cr2O7
Why titrant is taken in burette?
Titrant is always taken in burrete because it volume is unknown. As burrete is calibrated so we can accurately findout how much volume of titratnt is used to complete chemical reaction.
What is different between titrant and analyte?
Titrant is the solution of known concentration whereas analyte is the solution of unknown concentration.
Reference Book(s)
- Text book of Quantitative Chemical Analysis by Vogel’s 6th Edition
Reference Link(s)
- Titrant definition in chemistry (thoughtco.com)
