Prepartion of Primary Standard
Experiment 2 Preparation of Primary Standard solutions and Standardizing Acid and Base solutions
Objectives: The objective of this experiment is: 1- To prepare two primary standard solutions, KHP and Na2CO3 2- To standardize a sodium hydroxide solution using the prepared primary standard KHP. 3- To standardize a hydrochloric acid solution using the prepared primary standard Na2CO3. 4- To calculate the concentration of an unknown acid or base. Introduction A primary standard is a standard that is accurate enough that it is not calibrated. For a compound to be considered as a primary standard it should have several important characteristics, the most important of which are high purity, stability, low hygroscopicity, high solubility, and high molar mass. A primary standard solution is a solution of known concentration made from a primary standard. Primary standard solutions are used in determining the concentrations of other solutions to an extremely high accuracy. They are typically used in titrations and other analysis techniques as standardization solutions. A secondary standard solution, such as HCl solution, is a solution which must be standardized first against a primary standard, but afterwards, it will be stable enough for titrimetric work (Titration). Titration involves the gradual addition of a solution of accurately known concentration (standard solution) to another solution of unknown concentration (or vice versa), until the chemical reaction is complete. Titrations are based on reactions which go to completion rapidly. A reaction is complete when stoichiometric amounts of the reacting substances are combined. This is the stoichiometric point (equivalence point) in the titration. The equivalence point is detected visually using an indicator. An indicator is a substance (added at the beginning of the titration to the flask) that changes color at (or very near) the equivalence point. The point where the indicator actually changes color is called the end
Objectives: The objective of this experiment is: 1- To prepare two primary standard solutions, KHP and Na2CO3 2- To standardize a sodium hydroxide solution using the prepared primary standard KHP. 3- To standardize a hydrochloric acid solution using the prepared primary standard Na2CO3. 4- To calculate the concentration of an unknown acid or base. Introduction A primary standard is a standard that is accurate enough that it is not calibrated. For a compound to be considered as a primary standard it should have several important characteristics, the most important of which are high purity, stability, low hygroscopicity, high solubility, and high molar mass. A primary standard solution is a solution of known concentration made from a primary standard. Primary standard solutions are used in determining the concentrations of other solutions to an extremely high accuracy. They are typically used in titrations and other analysis techniques as standardization solutions. A secondary standard solution, such as HCl solution, is a solution which must be standardized first against a primary standard, but afterwards, it will be stable enough for titrimetric work (Titration). Titration involves the gradual addition of a solution of accurately known concentration (standard solution) to another solution of unknown concentration (or vice versa), until the chemical reaction is complete. Titrations are based on reactions which go to completion rapidly. A reaction is complete when stoichiometric amounts of the reacting substances are combined. This is the stoichiometric point (equivalence point) in the titration. The equivalence point is detected visually using an indicator. An indicator is a substance (added at the beginning of the titration to the flask) that changes color at (or very near) the equivalence point. The point where the indicator actually changes color is called the end