Question

what is the fomula of rust?​

Answer 1

Fe2O3.H2O...is the formula of rust.☺❤

Answer 2

The chemical equation for the formation of rust is:

Iron + Water + Oxygen = Rust

i.e. 4 Fe(s) + 6 H2O(l) + 3 O2(g) → 4 Fe(OH)3(s)

Then Fe(OH)3 dehydrates to produce Fe2O3.nH2O(s).

Thereby, the chemical formula for rust is Fe2O3.nH2O.