9 b] Write the principles and requirement of titrimetric analysis.
Principles :
- In a titration, the test substance (analyte of unknown concentration) is reacted with a reagent of exact known concentration (titrant, standard solution)
- This reagent is also known as a primary standard reagent and is prepared in the lab. This reagent is usually added from the burette where as the analyte is placed in a conical flask
Requirement :
- The stoichiometry ( ratio of reaction ) and the chemical nature of the reaction between titrant (standard solution ) & analyte should be know and well defined .
- The reaction between titrant & analyte should be rapid. This helps to achieve results quickly.
- There should be no side reaction between the titrant and molecules other than analyte that could react with the titrant in a similar manner. this means that there should be no side reaction & the reaction should be specific.
- there should be a marked change in some physical property of the solution when the reaction is complete and reaches the end point
- in the titration between acids & bases there is a marked increase in the pH of the reaction mixture when the reaction is complete.
- the end point at which an equivalent amount of titrant is added is called EQUIVALENCE POINT
- the point at which the reaction is observed to be complete is called the END POINT.