What is passivity of nitric acid?

nitric acid, produces a passive state in the metal, such that no further interaction with the nitric acid occurs. This induced passive state is caused by the oxidation of ferric nitrate to the oxide which resists further acid attack. Thus: Fe + 3HNO3 = Fe(NO3)3 + 3H.

What is passivity of iron which other metal show such phenomena?

IT is well known that the principal metals which show the phenomena of passivity are chromium, manganese, iron, cobalt and nickel. These elements have this in common that they form divalent ions, and that while possessing electrons, on Bohr’s theory, in the 4th-quantum orbit, their 3rd-quantum orbits are incomplete.

How is iron passivity removed?

The passivity can be removed by treating the inert iron with rubbing of sand paper.

Which of the following pairs of metals are rendered passive on reaction with concentrated nitric acid?

Iron is rendered passive with fuming nitric acid.

What causes the passive state of iron in ferric nitrate?

This induced passive state is caused by the oxidation of ferric nitrate to the oxide which resists further acid attack. Thus: However, the highly reactive nascent H extracts the oxygen from the ferric nitrate to form a film of insoluble and non-reactive ferric oxide at the surface that is responsible for the passive state of elemental iron.

What happens when ferric nitrate reacts with nitric acid?

Treating many metals such as iron with a strong oxidising agent such as conc. nitric acid, produces a passive state in the metal, such that no further interaction with the nitric acid occurs. This induced passive state is caused by the oxidation of ferric nitrate to the oxide which resists further acid attack.

What is required for the passivation of iron?

Thus, the passivation of iron requires both the presence of conc. nitric acid and the generation of nascent hydrogen. Use of dilute acid produces the normal reaction of a metal with an acid to produce the water soluble ferric nitrate plus hydrogen gas.

What happens when copper reacts with concentrated nitric acid?

The reaction proceeds slowly. Concentrated nitric acid renders the iron passive though – a small amount of Fe2O3 is formed and coats the metal, but that cannot be oxidised any further and the reaction then stops. What will happen when copper will be reacted with hot and concentrated nitric acid?