Question

#3, #4, #5

Why is the corrosion of car bodies worse in cities that use salt on the streets in the winter than in cities that do not use salt? Why are copper straps (rather than iron straps or bent over nails) used to hold household copper wire lines in place? When an iron post is immersed in water, rust forms at the water line and the iron post pits below the water line. Explain why this happens. Why do aluminum pots and pans develop a pitted surface when table salt is added to the cooking water?

Answer 1

3. Copper straps are used because they are resistant to corrosion and heat.

4. This happens because water conatins certain dissolved gases like oxygen that can lead to the corrosion of the metal

5. Pitting is a type of corrosion and this occurs because of the reaction between chloride from salt, oxygen from water and aluminium. However when undissolved salts are added, the chloride can attack only the passive layer and therefore it leaves pits where it removes the oxide.