Explain the principle of removal of rust stains from clothes using oxalic acid solution.

Explanation

Rust is `Fe_(2)O_(3).` Ferric `(Fe^(3+)` ion reacts with oxalate `(C_(2)O_(4)^(2-))` ion to form a complex ion that is soluble in water.
`H_(2)C_(2)O_(4)" [oxalic acid]" hArr 2H^(+)+C_(2)O_(4)^(2-)" [oxalate ion]"`
`Fe^(3+)+3C_(2)O_(4)^(2-) rarr underset(" Complex ion (soluble)")([Fe(C_(2)O_(4))_(3)]^(3-)`
The clothes are first treated with oxalic acid solution and then rinsed well with water 10 remove the rust stains.