Steel, an alloy consisting predominantly of iron, is widely used in construction, but it is highly susceptible to corrosion when exposed to water and oxygen.
(i) State the systematic chemical name for the compound commonly known as rust.
(ii) Write the chemical formula for the main anhydrous transition metal oxide present in rust.
During the corrosion process, neutral iron atoms lose electrons to form iron(III) ions:
Fe→Fe3++3e− \text{Fe} \rightarrow \text{Fe}^{3+} + 3\text{e}^- Fe→Fe3++3e−Which type of reaction is represented by this electron-loss process? Select the correct option from the following list:
Offshore steel oil rigs are often protected from seawater corrosion by attaching blocks of another metal as sacrificial anodes. (i) Name one metal from the reactivity series that is suitable to be used as a sacrificial anode to protect steel.
(ii) Explain, in terms of reactivity and electrons, how this sacrificial metal protects the steel from rusting.
State two barrier methods (other than sacrificial protection) that are commonly used to prevent steel structures, such as bridge supports, from rusting.
