Question

in case of an impure metal, the rate of corrosion is....​

Answer 1

Impure metals are essentially collections of numerous micro electrodes which forms numerous micro chemical batteries whose electrodes will naturally corrode.Also, impurity means there’s much higher chance to find defects in that Material which, when exposed to some non-ideal environment, much more fragile to the attack of some environmental factors(e.g moisture,which can further assist the corrosion process) This is just some random thought that come to my mind, I believe there exist many more factors related to inpurity which assist the corrosion