What Is Sulfuric Acid Titration?
The acid-base titration method refers to a titration analysis method based on the proton transfer reaction of acid and base in water.
- (1) Determination of iron by potassium dichromate method
- Sample Dissolution of hot HCl SnCl 2 reduction Sodium tungstate (indicator) TiCl 3 reduction (excess) Add Cu 2+ (catalyst) Add water Add H 2 SO 4 + H 3 PO 4 mixed acid Add two Sodium aniline sulfonate (titration indicator) Titration with K 2 Cr 2 O 7 standard solution End point (green purple) Main effect of adding H 3 PO 4 :
- (1) Fe 3+ generates colorless Fe (HPO 4 ) 2 complex ions, making the endpoint easy to observe;
- (2) Reduce the ferroelectric pair potential to make the indicator's discoloration point potential closer to the equipotential point potential. The dichromate method for determining iron is the standard method for determining the total iron content in ore.
- (2) Determination of organic matter in wastewater
- Chemical Oxygen Consumption (COD) is an indicator for measuring the degree of water pollution and reflects the content of reducing substances in water. It is commonly measured by the K 2 Cr 2 O 7 method.
- Determination method: add excess K 2 Cr 2 O 7 solution to water sample, heat and reflux to oxidize organic matter to CO 2 , excess K 2 Cr 2 O 7 is titrated back with FeSO 4 standard solution, and ferrite is used to indicate the end of the titration. In the method, in the presence of a silver salt catalyst, 85 to 95% of the linear hydrocarbons are oxidized, and the aromatic hydrocarbons do not work, so the obtained results are not strict enough. [2]