Step 1: Understanding the Question:
We need to identify which of the given compounds acts as an antiseptic, which is an antimicrobial substance applied to living tissue. Step 2: Detailed Explanation:
(A) Salvarsan: An organoarsenic compound historically used as an antibiotic for syphilis.
(B) Thymol: A natural phenolic compound found in thyme oil that has strong antiseptic and antibacterial properties. It is often used in mouthwashes and ointments.
(C) Sulphanilamide: An early sulfonamide antibiotic (sulfa drug) used to treat bacterial infections internally.
(D) Chloramphenicol: A broad-spectrum antibiotic used to treat serious bacterial infections. Step 3: Final Answer:
Thymol is the antiseptic compound among the options.