Ferrous sulfate (FeSO4) is not classified as a primary standard due to its instability and lack of inertness. A primary standard must be stable, inexpensive, and possess consistent properties. The discussion highlights that ferrous ammonium sulfate (FAS) also does not meet the criteria for a primary standard, emphasizing the importance of understanding the characteristics required for such classification.
PREREQUISITESChemistry students, laboratory technicians, and professionals involved in analytical chemistry who seek to understand the criteria for primary standards and their applications in titration processes.