Mercury pigment can be completely removed by immersion in sodium thiosulfate.

• A. True
• B. False
• C. Both
• D. Neither

Answer: (B)

Mercury pigment is not reliably removed by simply soaking in sodium thiosulfate. Sodium thiosulfate can dissolve or neutralize certain residual reagents and some soluble metal complexes, but many mercury pigments form insoluble compounds or become physically trapped within tissue, so they persist despite immersion. In practice, not all forms of mercury pigment are amenable to complete removal with thiosulfate alone, and additional steps or different reagents are often needed. So the statement is not true.