Nitric acid is a strong acid that is colorless as a pure liquid but commercial nitric acid may be yellowish-brown. It is produced through a three-stage process involving the oxidation of ammonia over a platinum catalyst. It has many industrial uses including in explosives, fertilizers, dyes, and others. When reacted with metals, it produces metal nitrates and oxides of nitrogen. It is both an oxidizing and acidifying agent that can cause explosions when reacted with some metals like sodium or potassium. The document provides details on the manufacture, properties, uses, and reactions of nitric acid.

1. Nitric acid
HNO3
Prepared by:
Aras jabar --- Tishko mhamad
&
Balen hasan --- Shaxawan rahim
University of slemani
School of science
chemistry department

2. Content
• Introduction
• physical and chemical properties
• Manufacture of nitric acid
• Industrial uses
• Reactions of nitric acid

3. Introduction
• Nitric acid is a strong monoprotic acid and is almost
completely ionised in aqueous solution.. Nitric acid is a
resonance-stabilized acid allowing it to share its electrons
among its own bonds
• Molar mass: 63g/mol
• Colour Pure nitric acid is a colourless liquid.
But commercial nitric acid may be yellowish brown, due to the
presence of dissolved nitrogen dioxide.
• Odour: Nitric acid is a fuming, hygroscopic liquid, the fumes
of which give it a choking smell

4. Concentration
• Nitric acid can be concentrated up to 68%. It cannot be
concentrated beyond this percentage by simply boiling
because the aqueous solution of this concentration of nitric
acid forms a constant boiling mixture at 121oC. However, the
acid can be further concentrated by one of the following
methods
• By passing a mixture of nitrogen dioxide and air through the
68% aqueous solution. This solution can be further
concentrated by distilling it with concentrated sulphuric acid
under reduced pressure. By this method nitric acid of 98%
concentration can be obtained.
• If the 98% acid is cooled to -42oC, then pure nitric acid of
100% concentration crystallises out as colourless crystals

5. Concentration
• If the solution contains more than 86% nitric acid, it is referred to
as fuming nitric acid . Fuming nitric acid is characterized as white
fuming nitric acid and red fuming nitric acid, depending on the
amount of nitrogen dioxide present. At concentrations above
95%, it tends to develop a slight yellow colour due to its tendency
to adsorb water from the atmosphere into its crystal structure.
Pure anhydrous nitric acid (100%) is a colourless liquid with a
density of 1.522 g/cm³ which solidifies at -42 °C to form white
crystals and boils at 83 °C. When boiling in light, even at room
temperature, there is a partial decomposition with the formation
of nitrogen dioxide following the reaction

6. physical and chemical properties
• Acidity : Nitric acid is a very strong acid and dissociates very
highly, and is very corrosive. Nitric Acid’s Dissociation
Constant is 28 (Ka value)
• Taste: It is sour in taste due to acidic nature
• Density: Its density is 1.513 g cm-3 at 20oC. Thus pure
nitric acid is about 1½ times as dense as water while
commercial nitric acid has a lower density.
• Boiling point: Pure nitric acid boils at 86oC. However it
undergoes partial decomposition at this temperature.
• Melting point: When cooled below oC nitric acid freezes to
a white solid, which melts at - 42oC.
• Solubility: It is soluble in water in all proportions.

7. Redox nature
• Redox Nature Nitric Acid has two properties in redox
nature. It is dependant on how concentrated the acid
solution is. (It is a very strong oxidant)
• Nitric acid (conc): NO3- + 2H+ + e -> NO2 + H2O
• Nitric acid (dilute): NO3- + 4H+ +3e -> NO + 2H2O

8. Manufacture
• The manufacture of nitric acid is a three-stage process. The
first stage is the oxidation of ammonia and it uses a
platinum/rhodium catalyst
INDUSTRIAL PREPARATION OF NITRIC ACID
• On industrial scale, nitric acid can be prepared by the
following methods
• (a) CHILLI-SALT PETER's METHOD: By NaNO3
• (b) BRIKLAND-EYDE's METHOD: By using air
• (c) OSTWALD' s METHOD : By ammonia

9. OSTWALD' s METHOD
Materials used:
• Ammonia gas
• Water
• Oxygen gas Catalyst
• Platinum
• DETAILS OF PROCESS
First step
• PRIMARY OXIDATION (formation of nitric acid)
• Oxidation of ammonia is carried out in a catalyst chamber in which one part of
ammonia and eight parts of oxygen by volume are introduced. The temperature
of chamber is about 600 o C. This chamber contain a platinum gauze which
serves as catalyst.
• CHEMISTRY OF PRIMARY OXIDATION
• Oxidization of ammonia is reversible and exothermic process. Therefore
according to Le-Chatelier's principle., a decrease in temperature favour reaction
in forward direction. In primary oxidization 95% of ammonia is converted into
nitric oxide (NO)

10. OSTWALD' s METHOD
Second step
• SECONDARY OXIDATION
• (formation of nitrogen dioxide)
• Nitric oxide gas obtain by the oxidation of ammonia is very
hot. In order to reduce its temperature , it is passed through a
heat exchanger where the temperature of nitric oxide is
reduce to 150 o C. Nitric oxide after cooling is transferred to
another oxidizing tower where at about 50 o c it is oxidizing to
NO2.

11. OSTWALD' s METHOD
Third step
ABSORPTION OF NO2
(formation of HNO3)
• Nitrogen dioxide from secondary oxidation chamber is introduced
into a special absorption tower. NO2 gas passed through the tower
and water is showered over it. By the absorption, nitric acid
is obtained
• Nitric acid so obtain is very dilute. It is recycled in absorption tower
so that more and more NO2 get absorbed. HNO3 after recycle
becomes about 68% concentrated

12. OSTWALD' s METHOD
Fourth step
Concentration
In order to increase the concentrated of HNO3 ,
vapour of HNO3 are passed over concentrated
H2SO4. Being a dehydrating agent H2SO4,absorbs
water from HNO3 and concentrated HNO3 is
obtained

13. Industrial Use
• The Important Uses of Nitric Acid Are:
• Manufacture of Various Products such as:
• Explosives such asTrinitrotoluene (TNT),
Nitro-glycerine, Gun Cotton
• Ammonal Fertilisers such as calcium nitrate,
Ammonium Nitrate
• Nitrate Salts such as calcium nitrate, silver
nitrate, ammonium nitrate

14. Industrial Use
• Dyes, Perfumes, Drugs
• Synthetic fibres such as Nylon
• Can make Sulphuric acid from Nitric acid by Lead
Chamber process
• Used in Purification of silver, gold, platinum
• Used for carving designs on copper, brass, bronze
• Used to make “Aqua Regia” which dissolves the
noble elements (aqua regia is a mixture of more
than one type of acid)
• Used as a Laboratory reagent

17. With metals
With metals in general
• With cold dilute nitric acid
Metal + Nitric Acid Metal Sulfate + Water + Nitric Oxide
• With concentrated nitric acid (cold or hot)
Metal + Nitric Acid Metal Sulfate + Water + Nitrogen Di-Oxide

18. With metal
• Nitric acid behaves differently with different metals at different
concentrations
• With sodium, potassium and calcium the reaction is highly explosive.
• With magnesium and manganese
• With magnesium and manganese, cold and extremely dilute (1%) nitric
acid, reacts to yield hydrogen.
• With Copper (Zinc and Iron also)
• cold dilute nitric acid:
• Copper reacts with cold and dilute nitric acid to yield copper nitrate,
water and nitric oxide.
With concentrated nitric acid (cold or hot):
• Copper reacts with cold or hot concentrated nitric acid to yield copper
nitrate, water and nitrogen dioxide

19. With Turpentine (A Cool Prac)
• Turpentine is a combustible hydrocarbon. When a
few drops of turpentine are added to fuming or
very concentrated nitric acid, it bursts into flames
forming water, nitrogen dioxide and carbon
dioxide.
The overall reaction is:

20. Thanks for listening