Kjeldahl method: a measure of nitrogen content in a sample. Organic nitrogen is digested into ammonia with sulfuric acid and potassium sulfate. Finally, ammonia is back titrated with boric acid and then sodium carbonate.
- TitrationThe amount of ammonia in ammonium salts can be estimated quantitatively by distillation of the salts with sodium (NaOH) or potassium hydroxide (KOH), the ammonia evolved being absorbed in a known volume of standard sulfuric acid and the excess of acid then determined volumetrically; or the ammonia may be absorbed in hydrochloric acid and the ammonium chloride so formed precipitated as ammonium hexachloroplatinate, [NH4]2[PtCl6].
- Ammonia2 related topics with Alpha
Acid
1 linksMolecule or ion capable of either donating a proton , known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid.
Molecule or ion capable of either donating a proton , known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid.
An example is boron trifluoride (BF3), whose boron atom has a vacant orbital that can form a covalent bond by sharing a lone pair of electrons on an atom in a base, for example the nitrogen atom in ammonia (NH3).
Neutralization is the basis of titration, where a pH indicator shows equivalence point when the equivalent number of moles of a base have been added to an acid.
Sulfuric acid
1 linksMineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formula H2SO4.
Mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formula H2SO4.
In particular, "10 M" sulfuric acid (the modern equivalent of chamber acid, used in many titrations), is prepared by slowly adding 98% sulfuric acid to an equal volume of water, with good stirring: the temperature of the mixture can rise to 80 °C (176 °F) or higher.
Reacting the ammonia produced in the thermal decomposition of coal with waste sulfuric acid allows the ammonia to be crystallized out as a salt (often brown because of iron contamination) and sold into the agro-chemicals industry.