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Nitrification is the biological oxidation of ammonia to nitrate via the intermediary nitrite. Nitrification is an important step in the nitrogen cycle in soil . The process of complete nitrification may occur through separate organisms [ 1 ] or entirely within one organism, as in comammox bacteria.
Theoretical oxygen demand (ThOD) is the calculated amount of oxygen required to oxidize a compound to its final oxidation products. [1] However, there are some differences between standard methods that can influence the results obtained: for example, some calculations assume that nitrogen released from organic compounds is generated as ammonia, whereas others allow for ammonia oxidation to ...
In environmental chemistry, the chemical oxygen demand (COD) is an indicative measure of the amount of oxygen that can be consumed by reactions in a measured solution.It is commonly expressed in mass of oxygen consumed over volume of solution, which in SI units is milligrams per liter (mg/L).
Nitric oxide (nitrogen oxide or nitrogen monoxide [1]) is a colorless gas with the formula NO.It is one of the principal oxides of nitrogen.Nitric oxide is a free radical: it has an unpaired electron, which is sometimes denoted by a dot in its chemical formula (• N=O or • NO).
In the NO − 3 anion, the oxidation state of the central nitrogen atom is V (+5). This corresponds to the highest possible oxidation number of nitrogen. Nitrate is a potentially powerful oxidizer as evidenced by its explosive behaviour at high temperature when it is detonated in ammonium nitrate (NH 4 NO 3), or black powder, ignited by the shock wave of a primary explosive.
The Kjeldahl method or Kjeldahl digestion (Danish pronunciation: [ˈkʰelˌtɛˀl]) in analytical chemistry is a method for the quantitative determination of a sample's organic nitrogen plus ammonia/ammonium (NH 3 /NH 4 +).
The formal oxidation state of the nitrogen atom in nitrite is +3. This means that it can be either oxidized to oxidation states +4 and +5, or reduced to oxidation states as low as −3. Standard reduction potentials for reactions directly involving nitrous acid are shown in the table below: [4]
A common nitrate test, known as the brown ring test [2] can be performed by adding iron(II) sulfate to a solution of a nitrate, then slowly adding concentrated sulfuric acid such that the acid forms a layer below the aqueous solution. A brown ring will form at the junction of the two layers, indicating the presence of the nitrate ion. [3]