preparation and uses of nitric acid

preparation and uses of nitric acid

1. Nitric acid By Amir Riaz Bs chemistry

2. introduction Nitric acid is a colorless liquid that is used in manufacture of inorganic and organic nitrates and nitro compounds for fertilizers, dye intermediates, explosives, and many different organic chemicals.

3. Structure, physical and chemical properties of nitric acid It is a strong, monoprotic acid and is almost completely ionized in aqueous solution. Nitric acid is a resonance-stabilized acid allowing it to share its electrons among its own bonds. Physical Properties: Molar mass: 63g/ mol Color: Pure nitric acid is a colorless liquid but commercial nitric acid may be yellowish brown due to presence of dissolved nitrogen dioxide. Odour : Nitric acid is a fuming, hygroscopic liquid, the fumes of which fumes gives it a choking smell.

4. Cont … Acidity: Nitric acid is a strong acid and dissociates very highly and is very corrosive. Nitric acid dissociation’s constant is 28 ( Ka value) Taste: It is sour in taste due to acidic in nature. Density: 1.513gcm -3 at 20 ° C. Thus pure nitric acid is about 1 times as dense as water while commercial nitric acid has a lower density.  

5. Cont … Boiling point : Pure nitric acid boils at 86 ° C. However it undergoes partial decomposition at this temperature. Melting point: When cooled below 0 ° C, nitric acid freezes to a white solid, which melts at -42 ° C. Solubility: It is soluble in water in all proportions.

6. Types of nitric acid Fuming nitric acid: A red liquid made by bubbling NO 2 gas through concentrated HNO 3 . Concentrated nitric acid: Its density is 1.5, containing 98% HNO 3 . Strong nitric acid: Its density is 1.4, containing 65% HNO 3 .

7. Industrial preparation of nitric acid On industrial scale, nitric acid can be prepared by the following methods: Chilli -salt peter’s method: By NaNO 3 and H 2 SO 4 react to produce NaHSO 4 and HNO 3. Brikland-Eyde’s method: By using air Ostwald’s method: By ammonia

8. Manufacturing of nitric acid The manufacture of nitric acid is a three stage process. The first stage is the use of ammonia and it uses a platinum/rhodium catalyst.

9. Raw materials Ammonia Water Air Catalyst (platinum-rhodium gas)

10. Steps in the production Oxidation of ammonia NH 3 Oxidation of nitric oxide Absorption of NO 2

11. OSTWALD’S METHOD ;1 st STEP Primary oxidation (formation of nitric acid): Oxidation of nitric acid is carried out in catalyst chamber in which one part of ammonia and eight parts of oxygen by volume are introduced. The temperature of chamber is about 600 ° C. This chamber contains a platinum gauze which serves as a catalyst. Chemistry of primary oxidation: Oxidation of ammonia is reversible and exothermic process. Therefore according to Le- Chateliars principle, decrease in temperature favors the reaction in forward direction. In primary oxidation, 95% of ammonia is converted to nitric oxide(NO). 4NH 3 + 5O 2 4NO + 6H 2 O

12. CONT… ;2 ND STEP Secondary oxidation (formation of nitrogen dioxide): Nitric oxide gas obtained by the oxidation of ammonia, is very hot. In order to reduce its temperature, it is passed through aat exchanger where the temperature of nitric oxide is reduce to 150 ° C. Nitric oxide after the cooling, is transferred to another oxidizing tower where at about 50 ° C, it is oxidizing to NO 2 . 2NO + O 2 2NO 2

13. CONT ; 3 RD STEP Absorption of NO 2 ( formation of HNO 3 ): Nitrogen dioxide from secondary oxidation chamber is introduced into special absorption tower. NO 2 gas passed through the tower and water is showered over it. By the absorption, nitric acid is obtained. 3NO 2 + H 2 O 2HNO 3 + NO Nitric acid obtained is very dilute. It is recycled in absorption tower so that more and more NO 2 get absorbed. HNO 3 after recycle becomes about 68% concentrated.

14. Cont … ; 4 TH STEP Concentration: In order to increase the concentration of HNO 3 , vapors of HNO 3 are passed over concentrated H 2 SO 4 . Being a dehydrating agent, H 2 SO 4 absorbs water from the HNO 3 and concentrated HNO 3 is obtained.

15. Industrial uses The important uses of nitric oxide are manufacture of various products such as: Explosives e.g TNT, Nitro-glycerin, Gun cotton, Ammonal Fertilizers such as calcium nitrate, ammonium nitrate Nitrate salts such as calcium nitrate, silver nitrate, ammonium nitrate Dyes, perfumes, Drugs Synthetic fibers such as Nylon For sulphuric acid production from nitric acid by the lead chamber process In purification of silver, gold, platinum For carving designs on copper, brass, bronze To make “Aqua Regia ” which dissolves noble elements

16. PRECAUTIONS WHILE USING NITRIC ACID FIRE Non flammable under normal conditions but highly reactive. Releases toxic and irritating fumes when heated. HEALTH Highly corrosive Shot term ingestion can cause burns to skin parts to digestive system Long term inhalation can cause the lungs diseases such as bronchitis an dcan cause tooth erosion.

17. Cont … Environment: Avoid release in the environment Inform the Environmental agency of industrial release incidents

18. Introduction To hcL Hydrochloric acid is a colourless and odourless solution of hydrogen chloride and water with chemical formula HCl. Once commonly referred to as muriatic acid or spirit of salt, this acid is a highly corrosive chemical compound with several applications in industry.

19. HCl is also re fe r red as spirit of salt H Cl is gas at room temperature Having p H 3.01

20. Hcl application Used in manufact ure of organic acid Such as use to produce PVC HCl as cleaning agent Extrem ely powerful and is recommended as a cleaner . Used to neutralize HCl use to neutrliz e water in swimming pool by chemicals. Used to regulate p H level

21. Use in activating oil wells process called oil well acidization . Method is use to accelerate oil production from the well .

22. Applications of hcl pH control and neutr ali zation agent Control basicity of solutions OH - + HC l H 2 O + OH - In industry demanding purity like food pharmaceuticals drinking water . High quality HCl is use to control the pH of process water stream .

23. Raw Matreial Nacl salt Watr Electricity