A steel support frame in an outdoor fountain is in contact with water and air. Pieces of zinc are attached to the frame. A maintenance worker suggests replacing the zinc with metal X. Metal X is less reactive than iron.
Why would metal X fail to protect the steel by sacrificial protection?
Metal X would corrode in preference to the iron, so it would be used up too quickly.
Metal X would stop water reaching the iron, but it would not stop oxygen reaching it.
Only zinc is reactive enough to protect iron, so any other metal would fail.
Iron would corrode in preference to metal X because iron is more reactive.
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.