Direct chemical attack is defined as an attack arising from direct exposure of a bare metal surface to corrosive caustic liquids or gaseous agents.

Direct chemical attack is defined as an attack arising from direct exposure of a bare metal surface to corrosive caustic liquids or gaseous agents.

• A. Pitting
• B. Uniform etch
• C. Direct exposure of a bare surface to corrosive caustic liquids or gaseous agents
• D. Electro-chemical attack

Answer: (C)

Direct chemical attack means corrosion that happens when a bare metal surface is exposed directly to corrosive caustic liquids or gaseous agents, causing dissolution by a chemical reaction rather than through an electrochemical process. This definition matches the statement, highlighting that the attack arises from direct contact with caustic substances without the involvement of a galvanic cell or electrolyte-driven redox reactions. Pitting and uniform etch describe specific patterns of corrosion, often involving electrochemical processes or localized cells, rather than a direct chemical dissolution of a clean surface. Electro-chemical attack explicitly involves electrochemical reactions across an electrolyte with anodic and cathodic areas.

Direct chemical attack means corrosion that happens when a bare metal surface is exposed directly to corrosive caustic liquids or gaseous agents, causing dissolution by a chemical reaction rather than through an electrochemical process. This definition matches the statement, highlighting that the attack arises from direct contact with caustic substances without the involvement of a galvanic cell or electrolyte-driven redox reactions.

Pitting and uniform etch describe specific patterns of corrosion, often involving electrochemical processes or localized cells, rather than a direct chemical dissolution of a clean surface. Electro-chemical attack explicitly involves electrochemical reactions across an electrolyte with anodic and cathodic areas.