Answer: Synthesis reaction
Explanation:
Corrosion is the process of slow eating away of metal due to attack of atmospheric gases on the surface of metal resulting into formation of compounds such as oxides, sulfides , carbonates etc is called as corrosion.
Corrosion of iron is called as rusting. Rust is hydrated ferric oxide [tex](Fe_2O_3.xH_2O[/tex].
Synthesis reaction is a chemical reaction in which two reactants are combining to form one product.
[tex]4Fe+3O_2\rightarrow 2Fe_2O_3[/tex]