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NH 2 − is a stronger base than the hydroxide ion and so cannot exist in aqueous solution. The p K a value of ammonia is estimated to be approximately 34 ( c.f. water, 14 [ 3 ] [ 4 ] ). Aprotic inorganic nonaqueous solvents
The procedure can also be used to assist in the analysis of complex acid mixtures containing sulfuric acid where resorting to titration in non-aqueous media is not feasible. The reaction enthalpy for the formation of barium sulfate is a modest −18.8 kJ/mol. This can place a restriction on the lower limit of sulfate in a sample which can be ...
Though solids are usually dissolved into an aqueous solution, other solvents such as glacial acetic acid or ethanol are used for special purposes (as in petrochemistry, which specializes in petroleum.) [19] Concentrated analytes are often diluted to improve accuracy. Many non-acid–base titrations require a constant pH during the
Gutmann, a chemist renowned for his work on non-aqueous solvents, described an acceptor-number scale for solvent Lewis acidity [4] with two reference points relating to the 31 P NMR chemical shift of Et 3 PO in the weakly Lewis acidic solvent hexane (δ = 41.0 ppm, AN 0) and in the strongly Lewis acidic solvent SbCl 5 (δ = 86.1 ppm, AN 100).
The distribution coefficient, log D, is the ratio of the sum of the concentrations of all forms of the compound (ionized plus un-ionized) in each of the two phases, one essentially always aqueous; as such, it depends on the pH of the aqueous phase, and log D = log P for non-ionizable compounds at any pH.
The history of acid-base titration dates back to the late 19th century when advancements in analytical chemistry fostered the development of systematic techniques for quantitative analysis. [5] The origins of titration methods can be linked to the work of chemists such as Karl Friedrich Mohr in the mid-1800s. [5]
The volumetric titration is based on the same principles as the coulometric titration, except that the anode solution above now is used as the titrant solution. The titrant consists of an alcohol (ROH), base (B), SO 2 and a known concentration of I 2. Pyridine has been used as the base in this case. One mole of I 2 is consumed for each mole of ...
Cerimetry or cerimetric titration, also known as cerate oximetry, is a method of volumetric chemical analysis developed by Ion Atanasiu. It is a redox titration in which an iron(II)–1,10-phenanthroline complex color change indicates the end point. Ferroin can be reversibly discolored in its oxidized form upon titration with a Ce 4+ solution ...