Nitric+acid

Nitric Acid (HNO3) is a colorless, but sometimes yellow, with a concentration of 68%. Nitric Acid is also highly corrosive and a strong toxic mineral acid, belonging to the group of inorganic acids. As shown through its name, Nitric Acid has a strong acidity which allows it to take part in oxidation reactions. The most common form of oxidation reaction involving Nitric acid are generally with metals, however it does react with some nonmetals. __Properties__ - colorless - melting point = -44F - boiling point = 181F - soluble in water - becomes a solid when cooled (in purest form) - mass = 62.995642903 g mol-1



While there are some more recreational uses for Nitric Acid, it is still a very strong and reactant acid so it's important to keep it's toxicity in mind when dealing with this compound.
 * The following are the main uses of nitric acid:**
 * 1) It is used in the production of ammonium nitrate for fertilizers.
 * 2) It is used for making plastics
 * 3) It is used in the manufacture of dyes
 * 4) It is used for making explosives such as nitroglycerine
 * 5) When it is combined with hydrochloric acid it forms an element called aqua regia which is a reagent that is capable of dissolving gold and platinum.
 * 6) It is used in a colorimetric test to distinguish heroin and morphine.
 * 7) Nitric acid is commonly used in science laboratories at schools for experimenting when specifically testing for chloride. This is done by adding a sample with silver nitrate solution and nitric acid to test if a white precipitate, silver chloride is present.
 * 8) Nitric acid is used in the field of medicine in its pure state as a caustic to get rid of chancres and warts. Diluted solutions are used in the treatment of dyspepsia.
 * 9) Nitric Acid is its use as rocket fuel in liquid form, as seen in the BOMARC missile.
 * 10) It can also be used in a very low concentrated form to chemically age the wood resembling something of an oil finished wood.

Acid-base properties
Nitric acid is normally considered to be a [|strong acid] at ambient temperatures. There is some disagreement over the value of the acid dissociation constant, though the [|pKa] value is usually reported as less than –1. This means that the nitric acid in solution is fully dissociated except in extremely acidic solutions. The pKa value rises to 1 at a temperature of 250 °C. [|[3]] Nitric acid can act as a base with respect to an acid such as sulfuric acid. HNO3 + 2H2SO4 NO2+ + H3O+ + 2HSO4–; //K// ~ 22 The nitronium ion, NO2+, is the active reagent in [|aromatic nitration] reactions. Since nitric acid has both acidic and basic properties it can undergo an autoprotolysis reaction, similar to the [|self-ionization of water] 2HNO3 NO2+ + NO3– + H2O

** Reactions with metals and strong oxidizing properties **
Nitric acid reacts with most metals. This characteristic has made it a common agent to be used in [|acid tests]. Very dilute nitric acid acts as a typical [|acid] to react with active metals. For example, strongly [|electropositive] metals, such as [|magnesium] react with nitric acid as with other acids, reducing [|hydrogen]. Mg + 2 H+ → Mg2+ + H2 Note that only [|Magnesium], [|Manganese] and [|Zinc] can liberate H2 gas from very dilute nitric acid. Others give the nitrogen oxides. [|[4]] However, both dilute and concentrated nitric acid is a strong oxidizing agent as shown by its large positive [|reduction potential] (E0r) and does not react with metals in the same way as most other [|acids]. [|Nitrogen monoxide] is reduced from the dilute acid reacting with metals while [|nitrogen dioxide] is reduced from the concentrated one. [|Hydrogen] is not evolved. NO3- + 4 H+ + 3 e- → NO + 2 H2O, E0r = 0.96 VNO3- + 2 H+ + e- → NO2 + H2O, E0r = 0.79 V Nitric acid can oxidize non-active metals such as [|copper] and [|silver]. With these non-active or less electropositive metals the products depend on temperature and the acid concentration. For example, [|copper] reacts with dilute nitric acid at ambient temperatures with a 3:8 stoichiometry. 3 Cu + 8 HNO3 → 3 Cu2+ + 2 NO + 4 H2O + 6 NO3- The nitric oxide produced may react with atmospheric oxygen to give [|nitrogen dioxide]. With more concentrated nitric acid, nitrogen dioxide is produced directly in a reaction with 1:4 stoichiometry. Cu + 4 H+ + 2 NO3− → Cu2+ + 2 NO2 + 2 H2O Most metals react with nitric acid to give the corresponding nitrates. [|[4]] Some other [|metalloids] and metals give the oxides, for instance, [|Sn], [|As] , [|Sb] , [|Ti] are oxidized into SnO2, As2O5, Sb2O5 and TiO2 respectively. [|[4]] Some [|precious metals], such as pure [|gold] and platinum group metals do not react with nitric acid, though pure gold does react with [|aqua regia] , a mixture of concentrated nitric acid and [|hydrochloric acid]. However, some less noble metals ( [|Ag], [|Cu] , ...) present in some [|gold alloys] relatively poor in gold such as [|colored gold] can be easily oxidized and dissolved by nitric acid, leading to colour changes of the gold-alloy surface. Nitric acid is used as a cheap means in [|jewelry] shops to quickly spot low-gold alloys (< 14 [|carats] ) and to rapidly assess the gold purity. Being a powerful oxidizing agent, nitric acid reacts violently with many non-metallic compounds and the reactions may be explosive. Depending on the acid concentration, temperature and the [|reducing agent] involved, the end products can be variable. Reaction takes place with all metals except the [|noble metals] series and certain [|alloys]. As a general rule, oxidizing reactions occur primarily with the concentrated acid, favoring the formation of [|nitrogen dioxide] (NO2). However, the powerful oxidizing properties of nitric acid is [|thermodynamic] in nature, but sometimes its oxidation reactions are rather kinetically non-favored. The presence of small amounts of [|nitrous acid] (HNO2) greatly enhance the rate of reaction. [|[4]]

** Reactions with non-metals **
Being a powerful [|oxidizing acid], nitric acid reacts violently with many organic materials and the reactions may be explosive. Reaction with non-metallic elements, with the exceptions of nitrogen, oxygen, [|noble gases], [|silicon] and [|halogens] , usually oxidizes them to their highest [|oxidation states] as acids with the formation of [|nitrogen dioxide] for concentrated acid and [|nitric oxide] for dilute acid. C + 4 HNO3 → CO2 + 4 NO2 + 2 H2O or 3 C + 4 HNO3 → 3 CO2 + 4 NO + 2 H2O Concentrated nitric acid oxidizes I2, P4 and S8 into HIO3, H3PO4 and H2SO4 respectively. [|[4]]