Nitric Acid 69% for trace metal analysis (ppt)

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Nitric acid (HNO3) is the best known and most stable oxygen acid of nitrogen. The acid has been produced on a large scale since 1908 using the Ostwald process by catalytic oxidation of ammonia. The ammonia is first produced from atmospheric nitrogen and hydrogen using the Haber-Bosch process.

The salts of nitric acid are called nitrates. The name nitric acid derives from the trivial names of some alkali and alkaline earth salts of the acid, which end with the designation saltpeter, such as E.g.: Sodium nitrate (Chiles nitrate), potassium nitrate (potassium nitrate), ammonium nitrate (ammonium nitrate), calcium nitrate (lime nitrate or wall nitrate), barium nitrate (barite nitrate). Until 1908, nitric acid was obtained from the various types of nitrate by adding a strong, non-volatile acid (sulphuric acid). The name of the salts of nitric acid nitrates is also very often used to name some organic compounds of nitric acid - namely the esters of nitric acid. So e.g. For example, the methyl ester of nitric acid is called methyl nitrate (see also nitrates), although the bonding conditions in the esters are completely different from those in the salts. To make matters worse and to increase the confusion even more, some special esters of nitric acid are neither correctly referred to as esters nor incorrectly as nitrates in colloquial speech, but as so-called nitro compounds, such as e.g. B. nitroglycerin (correct name: glycerol trinitrate) or nitrocellulose or cellulose nitrate.

As a strong inorganic acid, nitric acid is largely dissociated in aqueous solution and is one of the mineral acids. The pure acid is colorless and has a pungent odor. It is used in the production of fertilizers, dyes and explosives, among other things.

In the writing De inventione veritatis from the 12th century it is mentioned that as early as the 9th century the Arab alchemist Geber prepared crude nitric acid ("Aqua dissolutiva") by dry heating of saltpeter (Latin sal petrae = rock salt; KNO3), Cyprian vitriol (CuSO4 5 H2O) and alum (KAl(SO4)2 12 H2O). In the 13th century, Albertus Magnus is said to have used nitric acid to separate gold and silver (aqua fortis). However, many writings were attributed to Albertus Magnus only to give them greater weight, probably including those on the use of nitric acid. Later, saltpetre was heated with iron vitriol (FeSO4 7 H2O), which gave higher yields at lower temperatures.

In the middle of the 17th century, J. R. Glauber obtained pure spiritus nitri by reacting and distilling nitre with sulfuric acid, a laboratory process for the production of nitric acid that is still used today and which was also called aqua fortis or aqua valens in the Middle Ages and strong water in the English-speaking world. In the middle of the 18th century, A. L. Lavoisier recognized the chemical elements nitrogen and oxygen as components of nitric acid. The exact composition was determined by Henry Cavendish, who also succeeded in synthesizing it from the nitrogen in the air by electrical discharge.

Efficient production only began at the beginning of the 19th century, when cheap sulfuric acid and Chilean nitrate were available in sufficient quantities. Combustion of air in an electric arc was also developed into a large-scale process (Birkeland-Eyde process, after Kristian Birkeland and Sam Eyde), which, however, was only competitive in countries with cheap electricity. The catalytic oxidation of ammonia over platinum was discovered by CF Kuhlmann (1838). However, until the invention of ammonia synthesis by Haber and Bosch, ammonia remained too expensive compared to Chilean nitrate. At the beginning of the 20th century, Wilhelm Ostwald developed the production of nitric acid from ammonia to industrial maturity. The cheap ammonia oxidation has now replaced all other large-scale processes.
manufacturing

Technically, nitric acid has been produced since 1908 using the Ostwald process. This is the catalytic oxidation of ammonia. The ammonia-air mixture is passed quickly (1/1000 s contact time) through hot platinum-rhodium mesh (catalyst). At 800 °C, nitrogen monoxide is formed, which when cooled with excess oxygen forms nitrogen dioxide and then reacts with water in trickling towers to form around 60% nitric acid. The 60% nitric acid can be concentrated by distillation to 68%, which corresponds to the azeotrope with a maximum boiling point (122 °C). Higher concentrations can be achieved by rectification (dewatering) with sulfuric acid (H2SO4) or with an aqueous magnesium nitrate solution (Mg(NO3)2) or by treating dinitrogen tetroxide (N2O4) with the stoichiometrically required amount of oxygen (or air) and water .

On a laboratory scale, nitric acid can be produced by reacting concentrated sulfuric acid with nitrates. Prior to 1908, nitric acid was obtained by this process using sodium nitrate (Chilean nitrate).

NaNO3 + H2SO4 ⟶ NaHSO4 + HNO3

Frequently occurring contamination of the acid with halogens or hydrogen halides can be removed by adding silver nitrate and subsequent distillation. Anhydrous nitric acid is obtained, starting from an acid which has been highly concentrated by distillation, by passing inert gas through it or by distillation over phosphorus pentoxide or oleum.

Properties - nitric acid

In its pure state, nitric acid is colorless. However, concentrated nitric acid decomposes easily (especially when exposed to light) and often has a yellowish or reddish hue due to the nitrogen dioxide (NO2) dissolved in it.

4 HNO3 ⟶ 4 NO2 + 2 H2O + O2

Pure nitric acid containing free nitrogen dioxide is called fuming nitric acid. It contains over 90% HNO3, has a strong oxidizing effect and can ignite some easily combustible substances; Therefore, nitric acid from 70% is considered oxidizing. Nitric acid, colored yellow by dissolved nitrogen dioxide, can be decolorized by a small amount of urea, or better yet, urea nitrate.

Nitric acid is both a strong oxidizing agent and a strong acid. Nonmetallic elements such as carbon, iodine, phosphorus and sulfur are oxidized to their oxides or oxoacids by concentrated nitric acid to form nitrogen dioxide, for example

S + 6 HNO3 ⟶ H2SO4 + 6 NO2 + 2 H2O

In addition, many compounds are oxidized by nitric acid. Hydrochloric acid is oxidized to chlorine and chlorine dioxide.

Nitrates, the salts of nitric acid, are formed when metals or their oxides, hydroxides or carbonates react with nitric acid. Most nitrates are water soluble, and nitric acid is primarily used to produce soluble metal nitrates.

Nitric acid reacts with most metals to form water soluble nitrates. Exceptions are the precious metals gold, platinum and iridium. Aluminum, titanium, zirconium, hafnium, niobium, tantalum and tungsten also resist nitric acid through passivation. Furthermore, due to passivation, iron is resistant to cold nitric acid, and chromium is also resistant to hot nitric acid. A firmly adhering, impermeable oxide layer forms on the metal. Because you could separate gold and silver in this way, it used to be called the Scheidwasser. Mixtures of nitric acid with hydrochloric acid (aqua regia) or selenic acid also react with gold and platinum.

xanthoprotein reaction
Nitric acid yellows proteins containing aromatic amino acids such as L-phenylalanine or L-tyrosine by nitrating the benzene ring. This xanthoprotein reaction can be used to detect aromatic amino acids and proteins.

Physical properties of HNO3/H2O mixtures as a function of the concentration at 20 °C and 1.013 bar % by weight HNO3 0 10 20 30 40 50 60 70 80 90 100
density
(g/cm3) 1.00 1.05 1.12 1.18 1.25 1.31 1.37 1.42 1.46 1.48 1.513
viscosity
(mPa·s) 1.00 1.04 1.14 1.32 1.55 1.82 2.02 2.02 1.84 1.47 0.88
Mp (°C) 0 −7 −17 −36 −30 −20 −22 −41 −39 −60 −42
bp (°C) 100.0 101.2 103.4 107.0 112.0 116.4 120.4 121.6 116.6 102.0 86.0
p(HNO3) (mbar) 0.0 0.0 0.0 0.0 0.0 0.3 1.2 3.9 14.0 36.0 60.0
p(H2O) (mbar) 23.3 22.6 20.2 17.6 14.4 10.5 6.5 3.5 1.2 0.3 0.0
HNO3 (mol/L) 1.7 3.6 5.6 7.9 10.4 13.0 15.8 18.5 21 24.01
use

Nitric acid is one of the most important raw materials in the chemical industry. She serves:

- for the production of nitrates and fertilizers,
- as separating water for the separation (quartation) of gold and silver (silver reacts to form soluble silver nitrate),
- in mixtures with hydrochloric acid as aqua regia for dissolving gold, as well as for gilding and detecting gold,
- for pickling and firing of metals (graphic and galvanic technique),
- for polishing metals,
- to change fats (water solubility) for the purpose of cleaning,
- for the production of celluloid, nitro lacquers and zapon lacquers,
- in rocket propellants as oxidizers (WFNA and RFNA).
- for the nitration of organic substances in the production of dyes, medicines, disinfectants and explosives such as nitroglycerin or gun cotton

Because of the latter usability, the EU has included nitric acid in mixtures with a content of more than 3% as one of the restricted precursors for explosives since February 1, 2021, with the result that the use, possession, transfer and sale by and to persons is prohibited is not acting for professional or commercial purposes; the professional or commercial purpose must be checked upon sale and suspicious transactions must be reported.

According to police statements, concentrated nitric acid is also increasingly being used as a tool for burglary. Here, the nitric acid is used, among other things, in apartment buildings to attack the profile cylinders used in the apartment entrance doors.

proof
Like nitrates, nitric acid can be detected in the laboratory by the ring test and by lung's reagent.

safety instructions
Nitric acid has a corrosive effect on the skin, respiratory tract and mucous membranes. Inhalation of vapors may cause toxic pulmonary edema. This danger arises above all when heated or when the acid is concentrated. In high concentrations, it is a strong oxidizing agent and has an oxidizing effect. Nitric acid reacts with most metals to form toxic nitrogen dioxide. When working with nitric acid, protective goggles or a face shield, suitable protective gloves and a closed overall must be worn. If there is a risk of nitric acid vapors or nitrogen oxides being released in a room, a breathing apparatus must be worn. For this reason, nitric acid is not suitable for household cleaning purposes. Work in the laboratory is always carried out in a fume hood. A Teflon cap is recommended for bottles containing concentrated nitric acid.

FAQs

What is the CAS number of Nitric Acid?

The CAS number of Nitric Acid is 7697-37-2.

CAS Nitric Acid?

The CAS number of Nitric Acid is 7697-37-2.

CAS 7697-37-2?

The CAS number 7697-37-2 is assigned to Nitric Acid.

What does Nitric Acid 69% mean?

Nitric Acid 69% means that the mass fraction is 0.69. In other words, in a sample of 100 g Nitric Acid 69% the mass of 69 g Nitric Acid is present.

What is the purity of Nitric Acid?

The purity of Nitric Acid is 69%.

What does HNO3 69% mean?

HNO3 69% means that the mass fraction is 0.69. In other words, in a sample of 100 g HNO3 69% the mass of 69 g HNO3 is present.

What is the purity of HNO3?

The purity of HNO3 is 69%.