Hematein and hematin can be formed by combining with aluminum.

• A. True
• B. False
• C. Not specified
• D. Sometimes

Answer: (B)

In staining with hematoxylin, the active nuclear stain comes from the dye after it has been oxidized to hematein and forms a complex with a mordant, typically aluminum. The aluminum mordant binds with hematein to create the hematein-aluminum complex, which then binds to nucleic acids to produce the characteristic blue-purple nuclei.

Hematin, on the other hand, is a different chemical (an iron-containing heme derivative) and is not formed by reacting hematoxylin with aluminum. The mordanting process specifically involves hematein, not hematin, so the idea that aluminum can form both hematein and hematin is not correct.