Unlike electro-chemical attack, direct chemical attack changes occur at

• A. At the same point
• B. At distinct distances apart
• C. Only at the anodic region
• D. Only at the cathodic region

Answer: (A)

Direct chemical attack produces a uniform, surface-wide response. Since there’s no galvanic couple forming on the metal surface, there isn’t a separate anodic site and a cathodic site driving localized dissolution. The oxidizing agents attack the metal evenly across the exposed area, so the changes occur at essentially the same points over the surface. If you see attack concentrated at distinct spots or limited to anodic or cathodic regions, that points to electrochemical processes (galvanic or differential aeration) rather than a direct chemical attack.