The Weil technique uses both excess mordant and an oxidizer for the differentiation steps.

• A. True
• B. False
• C. Only oxidizer
• D. Only mordant

Answer: (A)

Differentiation in the Weil technique relies on creating selective decolorization so that only the desired structures stay stained. The oxidizer changes the chemical state of the dye–mordant complex, making it more prone to removal where binding isn’t strong. Using an excess mordant during differentiation then promotes stripping of loosely bound dye by providing more mordant to compete with tissue binding and to form complexes that are easier to wash away. The combination sharpens contrast and preserves staining where the interaction is strongest, which is why both an excess mordant and an oxidizer are used.