Which combination of environmental factors is primarily responsible for the formation of rust on iron surfaces?

• A. Contact with acids and bases
• B. High temperature and sunlight
• C. Presence of oxygen and water
• D. Exposure to carbon dioxide and nitrogen

Answer: (C)

Verified step by step guidance

1. Understand that rust formation on iron is a chemical process known as corrosion, specifically the oxidation of iron.
2. Recognize that rust forms when iron reacts with oxygen in the presence of water or moisture, leading to iron oxides.
3. Note that acids and bases can accelerate corrosion but are not the primary cause of rust formation.
4. Acknowledge that high temperature and sunlight alone do not cause rust; they may influence the rate but are not essential factors.
5. Conclude that the primary environmental factors responsible for rust are the presence of oxygen and water, which together enable the oxidation process.