The chemical action involving the movement of chemicals, on a molecular level, through intact materials is called?

• A. Penetration
• B. Degradation
• C. Breakthrough time
• D. Permeation

Answer: (C)

Permeation is the process by which a chemical moves through a protective material at the molecular level while the material remains intact. This distinction matters: penetration involves the chemical getting through a barrier by holes, tears, or openings, not through intact material. Degradation refers to damage or change to the barrier itself, not the passage of the chemical. Breakthrough time is the moment when permeation becomes detectable inside the barrier, i.e., the time until the chemical first appears on the inner surface, not the act of moving through. Since the question describes movement through intact materials, permeation is the correct term.