Question

What are the chemical formulae for galvanic corrosion of iron (rusting)?

Answer 1

Fe2O3.nH2O It is the formula of rusting hope it will help you  

Answer 2

$\huge\mathfrak\color{blue}{Answer}$

The formation of rust requires iron, water and oxygen. Although it's a complex process, the chemical equation is simply 4Fe + 3O2 + 6H2O → 4Fe(OH)3.