A painted steel leg supports an outdoor bench. The paint is scratched, exposing the iron in the steel. A zinc strip touches the exposed steel. Air and rainwater reach both metals.
What happens?
The zinc strip corrodes in preference to the iron because zinc is more reactive.
The zinc strip corrodes only after the iron because zinc is less reactive.
The zinc strip remains unchanged because the iron provides the sacrificial protection.
The zinc strip remains unchanged because sacrificial protection prevents either metal corroding.
118 exam-style questions on AQA GCSE Chemistry 10.3 Using materials, covering 10.3.1 Corrosion and its prevention, 10.3.2 Alloys as useful materials, and 10.3.3 Ceramics, polymers and composites. Each one has a worked solution and a mark scheme showing where the marks go.