Question

Name 1 element in which corrosion is not proved to be wasteful?

Answer 1

Aluminium/copper.
In these elements corrosion forms a thin oxide layer over its surface which prevents further corrosion. Hence thier corrosion is not a wasteful process.
U can also include all other metals which is protected by oxide layer frm corrosion.

Answer 2

hey there !!
Zinc and aluminium are such metals. This is because their oxides form a layer over metal's surface and are not flaky or powdery so dont get removed easily so corrosion is not proved to be wasteful