Single Choice

Pure conc. $$ HNO_3 $$ makes iron passive as the surface is covered with protective layer of

A$$ Fe_2O_3 $$
B$$ FeO $$
C$$ Fe_3O_4 $$
Correct Answer
D$$ Fe(NO_3)_3 $$

Solution

The passivity of iron is due to the formation of a thin insoluble and invisible iron film on surface which prevents its further reactions. The film is due to the formation of $$Fe_3O_4.$$

SIMILAR QUESTIONS

Metals and Non - metals

Iron is rendered passive by treatment with concentrated:

Metals and Non - metals

(a) Explain why metals usually do not liberate hydrogen gas with dilute nitric acid. (b) Name two metals which can however, liberate hydrogen gas from very dilute nitric acid.

Metals and Non - metals

(a) What happens when calcium reacts with chlorine? Write an equation of the reaction which takes place. (b) What happens when magnesium reacts with very dilute acid? Write an equation for the reaction involved.

Metals and Non - metals

Very dilute nitric acid reacts with iron to produce hydrogen.

Metals and Non - metals

The metal which reacts with $$HNO_{3}$$ to give five different products depending upon the concentration of the acid is :

Metals and Non - metals

Carbon can reduce copper oxide to copper but not CaO to Ca. Why?

Metals and Non - metals

Iron when treated with concentrated nitric acid

Metals and Non - metals

Hot and conc. nitric acid when reacts with copper, the gas obtained is

Metals and Non - metals

Reaction of zinc with cold and very dilute nitric acid yields

Metals and Non - metals

Zn gives hydrogen gas with $$ H_2SO_4 $$ and $$HCl$$ but not with $$ HNO_3 $$ because

Contact Details