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Nitric Acid

Nitric Acid Chemical Formula and Production

Nitric acid (chemical formula HNO3) is one of the most widely uses heavy chemicals used in acidic fertilizer production plant and explosives manufacturing process and storage million tonnes of each year. Pure nitric acid is a colorless high-density liquid, freezing point -41.6°C, boiling point 82.6°C and concentrated water solution have properties to photochemical dissociation and change to brown by liberating nitric oxide with very low pH level. Nitric acid manufacture by catalytic oxidation of ammonia by Oswald process and laboratory preparation find by distillation of reagent sodium or potassium nitrate with concentrated sulfuric acid. Commercially available nitric acid has a concentration of about 98 percent and fuming yellow or red HNO3 get by dissolving extra NO2.

Structural Formula of Nitrate Ion

The gas molecule of nitric acid has a planner structure and the same structure probably holds for crystalline solid. The N-O chemical bond distance in nitrogen dioxide are equal. The third N-O polar bond distance longer but bond energy lower than the corresponding single bond.  Therefore, the structures consist of roughly sp2 hybridized orbital at which nitrogen atom involving resonance hybrids. The nitrate ion symmetrical planner with  N-O bond distance 1.22, consist bond order of 1 and 1/3.

Nitric acid and nitrate ion structure, uses, and production formula in the chemical plant

Nitric Acid Production Process

Manufacture of pure nitric acid with molar mass 63 done by catalytic oxidation of ammonia (Ostwald process). But ammonia undergoes different types of oxidation reactions under various conditions in learning chemistry.

  • In the air, ammonia reacts but little to form nitrogen but in pure oxygen, it burns to form nitrogen and water.

4NH3 + 3O2 → 2N2 + 6H2O

  • When hot platinum gauze catalyst use, the mixture of ammonia and air (1:7) oxidized mostly to nitrogen monoxide.

4NH3 + 5O2 → 4NO + 6H2O

  • The liberated specific heat keeps the catalyst hot. Therefore, nitrogen monoxide cooled and mixed with oxygen to give dioxide. When the product passed into warm water under pressure to give HNO3 which causes acid rain in our environment.

4NO2 + 2H2O + O2 → 4HNO3

Chemical Activities of HNO3

Chemical activities of HNO3 discussed under neutralization reaction, chemical equilibrium reaction, oxidation reaction, and nitrating reagent. In water solution, HNO3 shows strong acid properties. Concentrated HNO3 in the presence of sulfuric acid attack aromatic hydrocarbon and thair derivatives to form nitro compounds. Some oxidizing activities are shown in the following reactions.

Cu + 4HNO3(conc) → 3Cu(NO3)2 + 2NO2 + 2H2O
Cu + 8HNO3(diluted) → 3Cu(NO3)2 + 2NO + 2H2O

Uses of Nitric Acid (HNO3)

The main storge consumption about 80% of strong nitric acid uses in the manufacture of ammonium nitrate (NH4NO3) which chiefly used as an acidic fertilizer plant but also use as an explosive in mining.

  1. It also uses (5 -10%) in making cyclohexanone and caprolactam as a route to nylon.
  2. Nitric acid confined to nitration in chemical reaction to produce nitroglycerine, nitrocellulose, and trinitrotoluene (TNT).
  3. These acids also used in the pickling of metals surface, oxidizer in rocket fuel, and in the manufacture of various nitrate.

Red fuming HNO3 molecule finds by dissolving N2O4, which is a superior nitrating reagent in chemistry. A mixture of concentrated nitric acid and sulfuric acid also uses to make strong nitrating reagent and storage like the nitronium ion (NO2+).