Which placard pictogram indicates a corrosive substance?

• A. A flame.
• B. A gas cylinder.
• C. The pictogram showing a hand and a surface being damaged by liquid (two test tubes).
• D. A skull and crossbones.

Answer: (C)

Hazard pictograms convey specific chemical risks, and the symbol showing a hand and a surface being damaged by a liquid communicates corrosion. This image indicates that the chemical can cause severe skin burns and eye damage and can also corrode metals. That direct message is what makes it the best indicator for corrosive substances. The flame pictogram signals flammability, the gas cylinder represents a compressed gas, and the skull-and-crossbones denotes acute toxicity. So the hand-and-surface corrosion symbol is the one that indicates corrosive material.