Steel food cans are coated with tin. Some steel car parts are galvanised (coated with zinc).
The reactivity series shows: zinc is more reactive than iron, and iron is more reactive than tin.
Both coatings are scratched so that the steel underneath is exposed to air and water.
Which statement is correct?
Both coatings still protect the steel, because both metals are a barrier around the scratch.
Only the tin coating still protects the steel, because tin is less reactive than iron, so tin does not corrode.
Only the zinc coating still protects the steel, because zinc is more reactive than iron, so zinc corrodes instead of the iron.
Neither coating protects the steel, because a coating only works when it is not damaged.
61 exam-style questions on OCR GCSE Chemistry 6.1 Improving processes and products, covering 6.1.1 Extracting metals industrially and by electrolysis, 6.1.2 Life cycle assessment and recycling, 6.1.3 Biological methods of metal extraction, 6.1.4 The Haber process and the production of fertilisers, 6.1.5 Alloys and their uses, 6.1.6 Corrosion and its prevention, 6.1.7 Comparing and selecting materials, and 6.1.8 Industrial conditions, rate and position of equilibrium. Each one has a worked solution and a mark scheme showing where the marks go.