Preparation of nitric acid(HNO3),Ostwald process,Brikeland Eye process

HNO₃(Nitric acid)

It is one of the important Oxo-acid of Nitrogen.In such Oxo-acid Nitrogen has +5 oxidation state.

HNO₃

1+x-5=0

X=+5

Preparation of HNO₃

(I) Lab method :- When potassium nitrate is treated with Sulphuric acid then nitric acid is obtained.

KNO₃+H₂SO₄→KHSO₄+HNO₃

(II.) Commercial method :- Nitric acid is obtained at large scale by using following method :-

(a) Birkeland Eyed process

(b) Ostwald process

(a) Birkeland Eyed method :-It is one of the important commercial method for the preparation of Nitric acid. When nitrogen is treated with oxygen then nitric acid is obtained. Such reaction is endothermic in nature. It is taken in presence of electric spark that produces more than 300⁰C temperature.

N₂+O₂ ⥦ 2 NO – Heat

Nitric oxide immediately react with oxygen and form nitrogen dioxide.

2NO + O₂ → 2NO₂

When nitrous acid is unstable in nature it dissociated into nitric acid and nitric oxide.

6HNO₂ → 2HNO₃ + 4NO₃ + 4NO + 2H₂O

In above reaction nitric oxide is obtained can be reused for the formation of NO₂.

(b) Ostwald Process

:- Such  is completed in following step:-

Step-1 Ammonia react with oxygen in presence of platinum catalyst at 600 to 700⁰C temperature Such reaction  is reversible an exothermic in nature.

2NH₃ + 2.5O₂  2NO + 3H₂O + Heat

Step-II  New nitric oxide in nitrogen dioxide in presence of oxygen.

2NO + O₂ → 2NO₂

Step- III  New NO₂ is Passess through water then nitric acid is obtained.

3NO₂ + H₂O → HNO₃ + NO

NO(Nitric acid) obtained in above reaction can be reused in the formation of nitric acid.

Properties :-

• It is known as aqua fort.
• It is Colourless liquid.
• Its is boiling point is 84.1⁰c.
• It is completely soluble in water.
• It is corrosive in nature.
• It is strong acid.

Chemical properties :-

Reaction due to acidic nature :- Nitric acid is known as mono basic acid or mono protic acid.

       HNO₃ → H⁺ + NO₃^–       Nitric acid react with metal.

Reaction with HCl :- When conc. HNO₃ react with conc. HCl then mixture is formed known as Aqua Regia.

In such mixture three part HCl and one part concentrated HNO₃ is taken. Such mixture can dissolve novel metal also like gold,Silver,Platinium .

FAQ.

Q. Preparation of nitric acid by in which process?

Ans-Ostwald process,Brikeland Eye process

Q. Formula of nitric acid?

Ans-HNO3

Q. Oxidation number of HNO3 in nitrogen?

Ans- +5