Ardit Cenalia | Unit 1
How are standard solutions prepared?
A standard solution is a solution that the concentration is known accurately. The concentration is normally given has mol/dm3. Then to be able to find a concentration of another substance with in the solution, a standard solution will be used.
While making the standard solution itself, it is important that the right mass of the substance is correctly measured. It is also important that all of this is successfully transferred to a volumetric flask; this is so that it will be used to make up the solution accurately.
An acid titre is able to be used as a standard solution, after the acid tire concentration has been established, through the use of titrating against the known concentration of the alkali solution.
The analysis of a chemical species is able to be accomplished by the use of standard solution. Varying concentration changes in their absorbance of light at particular wavelengths, and therefore the sample solution is compared to various known standard solution and their absorbance at certain wavelengths (this is done by using Beer’s law) can be capable of determining its concentration.
Standard solutions are also used within the industry. The solutions which are used in the standard solution will undergo rigorous tests by the manufacturers; this is so that they are able to prove their accuracy, before they are able to be used in the quality assurance of the products.
Titration is procedure that is used to find the volumes of solutions that react together. This means that it is called volumetric; there are three different types of volumetric titration:
- Direct titration method (DTM)
- This is a direct addition of standard titration to the analyte, in the presence of acid-base indictor till the reaction is completed than reaching the E.P (the colour change of the indicator)
- Indirect titration method (ITM)
- This is process in which the analyte do not react with the titrant directly but instead they are connected with the use of iodine.
- Back titration method (BTM)
- This is used for many reasons, this includes: when the sample contains impurities that interfere with forward titration, when the sample is not soluble in water or when the end-point is more easily identified than in forward titration.
At some point in titration, a base and an acid will achieve equilibrium and therefore the equation will be balanced. The equilibrium can only occur only once the end-point has been successfully reached. The process is when the solution of the analyte is prepared and then added to a conical flask with alongside an appropriate indicator, the sample which is to bed determined is called a titrant, and it is added drop by drop to the analyte, only until you are able to see a colour change with in the solution.