Should an acid be used to remove rust?

Acid does not remove rust, however the use of phosphoric acid on rust converts the iron oxide to iron phosphate, which in turn can be painted without the fear of rust forming. The iron phosphate...

It reacts with Iron Oxide

HCl+Fe2O3(Fe3O4)->FeCl+H2O

Rust is Fe2O3 ....it can not be removed by 1.HCl 2.H2So4 3.Edta..... but can remove by Oxalic Acid H2C2O4 Fe2O3(s) + 6 H2C2O4(aq) → 2 Fe(C2O4)3 3−(aq) + 3 H2O(l) + 6 H+(aq)

Oxalic acid