Iron is rendered passive by treatment with concentrated

Iron is rendered passive when treated with conc. :

Which fo the following metal is rendered passive by the action of highly concentrated nitric acid (~80%)?

The treatment of with concentrated KOH gives

The treatment of with concentrated KOH gives

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

The treatment of with concentrated NaOH gives

The treatment of with concentrated NaOH gives