It is a solution containing an accurately known concentration.A standard solution ideally has a high degree of purity and is stable enough that the concentration can be accurately measured after a long shelf time.
Types of Standard Solutions
A. Primary Standard Solution:
It is made from a highly pure, stable substance with a known consistent composition.It Does not absorb moisture or react with air easily.
1. Acid-Base Primary Standards:
- Sodium carbonate is used to Standardize Hydrochloric acid, Sulfuric acid.
- Potassium hydrogen phthalate is used to Standardize Sodium hydroxide.
- Tris(hydroxymethyl)aminomethane is used to Standardize Acids (e.g., HCl).
2. Redox Primary Standards:
- Potassium dichromate is used to Standardize Ferrous sulfate ,Sodium thiosulfate.
- Sodium oxalate is used to Standardize Permanganate
- Potassium iodate is used to Standardize Sodium thiosulfate.
3. Precipitation Primary Standards:
- Silver nitrate is used to Standardize Sodium chloride.
- Sodium chloride is used to Standardize Silver nitrate.
4. Complexometric Primary Standards:
- Zinc sulfate is used to Standardize EDTA solution.
- Magnesium sulfate is used to Standardize EDTA solution.
B. Secondary Standard Solution:
It is a solution whose concentration is not known exactly and must be standardized using a primary standard before use. These substances are usually unstable, hygroscopic, or react with atmospheric gases.
1. Acid-Base Secondary Standards:
- Hydrochloric acid is used to Standardize Sodium carbonate.
- Sulfuric acid is used to Standardize Sodium carbonate.
- Sodium hydroxide is used to Standardize Potassium hydrogen phthalate.
- Ammonium hydroxide is used to Standardize Hydrochloric acid.
2. Redox Secondary Standards:
- Potassium permanganate is used to Standardize Sodium oxalate.
- Sodium thiosulfate is used to Standardize Potassium dichromate or Iodate.
- Iodine solution is used to Standardize Sodium thiosulfate.
- Ferrous sulfate FeSO₄ is used to Standardize Potassium dichromate.
3. Precipitation Secondary Standards:
- Silver nitrate is used to Standardize Sodium chloride.
- Sodium chloride solution is used to Standardize Silver nitrate.
4. Complexometric Secondary Standards :
- EDTA solution is used to Standardize Zinc sulfate or Magnesium sulfate.
Related Topics:
Resource Person: Susmita