Aluminium becomes passive in

Give some examples for metals other than beryllium and aluminium that becomes passive on. treatment with concentrated nitric acid.

Aluminium is passive to concentrated nitric acid. Why?

Iron becomes passive in conc. "HNO"_(3) - Why ?

Iron becomes passive on treatment with

Metal which become passive with conc. HNO_(3)

Metal which become passive with conc. HNO_(3)