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Nitric Acid

Nitric Acid Chemical Formula

Nitric acid (chemical formula HNO3) is colorless, fuming, highly corrosive liquid, and most important heavy chemicals used in the acidic fertilizer production plant, explosives manufacturing process, and common laboratory reagent storage million tonnes of each year. Pure concentrated nitric acid is a high-density toxic liquid to burn skin, freezing point -41.6°C, boiling point 82.6°C and concentrated water solution have properties of photochemical decomposition to turns brown by liberating nitrogen dioxide (NO2) with very low pH level. Nitric acid manufacture by catalytic oxidation of ammonia (NH3) by the Oswald process or distillation of sodium or potassium nitrate with concentrated sulfuric acid is a pollutant of our environment that causes acid rain or snow. Commercially 98 percent concentrated nitric acid converted to yellow or red fuming acid by dissolved extra nitrogen dioxide in 98 percent acid solutions.

Structural Formula of Nitrate Ion

Nitric acid (chemical formula HNO3) and nitrate ion structure, uses, and production process

In learning chemistry, the gas phase nitric acid (HNO3) has a planner structural formula but nitrate ion has a planner symmetrical structure with a negative charge on resonance hybrid. The same general structure holds probably in solid forms of HNO3. The first two N-O chemical bond distances in HNO3 are equal but the third N-O polar bond distance longer than the first two due to low bond energy corresponding to the single bond.  The resonance hybrid of nitrate ion consists of roughly sp2 hybridized orbital at which the nitrogen atom involving resonance hybrids with symmetrical planner structure,  N-O bond distance 1.22, consists of a bond order of 1 and 1/3.

Chemical Production Process in Chemistry

The laboratory preparation formula for nitric acid defines the distillation of sodium or potassium salt of nitrate (KNO3 or NaNO3) with the concentrated sulfuric acid solution. In commercially, the production of pure nitric acid (molar mass or molecular weight = 63 gm/mol) is happened by heated ammonia with a suitable catalyst (Ostwald process) but ammonia undergoes different types of oxidation reactions under various conditions. For example, in the air, ammonia reacts to form nitrogen, in pure oxygen ammonia burns to form nitrogen and water.

The mixture of ammonia and air (1:7) oxidized most of the nitrogen by hot platinum gauze chemical catalyst to form nitrogen monoxide. The liberated specific heat keeps the catalyst hot. The heated nitrogen monoxide cooled and mixed with oxygen to get nitrogen dioxide which passed into warm water or soluble under pressure to yield a 60 percent dissolved solution of nitric acid that distilling by boiling point 122 °C produced concentrated 68.5 percent HNO3.

Physical and Chemical Properties

The pure or concentrated aqueous solutions of nitric acid define the properties of photochemical decomposition with very high dielectric constant, good ionizing solvent for electrolytes, and powerful oxidizing agent for the chemical compound. In dilute aqueous solution of nitric acid (molarity below 2M) behaves like a strong acid with little oxidizing power but if the concentration greater than 2M, HNO3 is a powerful oxidizing agent that attracts most of the metals by liberating hydrogen. Therefore, concentrated HNO3 in the presence of sulfuric acid attack aromatic hydrocarbon and their derivatives to form nitro compounds. Some oxidizing activities of the mixed acid shown in metals like copper, silver, and gold.

Uses of Nitric Acid

The main storage consumption about 80 percent of strong nitric acid uses in the manufacture of ammonium nitrate (NH4NO3) which is chiefly used as an acidic fertilizer plant, explosive in mining. Nitric acid also uses (5 -10 percent) in making cyclohexanone, caprolactam as a route to nylon, confined to nitration in chemical reaction for the production of nitroglycerine, nitrocellulose, and trinitrotoluene (TNT). These acids are also used in the pickling of metals surface, oxidizer in rocket fuel, for the manufacture of various nitrate salts. The formation of red fuming nitric acid molecule find by dissolving N2O4, which is a superior nitrating laboratory reagent in chemistry but a mixture of concentrated HNO3 and H2SO4 also uses to make a strong nitrating chemical compound, name as nitronium ion (NO2+).