Mercury® nitrate, reagent

Barbiturate metabolites are more heavily colored by the mercury(I) nitrate reagent (exception allobarbital), while unaltered barbiturates react more sensitively to the mercury(II)-diphenylcarbazone reagent (q.v.) [1]. 

Mercaptoethanol reagent 380 Mercury cations 144,311 Mercury lamps 20, 22 ff emission lines 23, 24 -, high pressure 22 ff -, technical data 23 Mercury(I) nitrate reagent 337 Mercury(II) salt reagent 340 Mesaconic acid 61 Mesoporphyrin 101, 102 Metal cations 310—312,398 Metal complexes 248, 398 Methanol, dipole moment 97 Methine dyestuffs 360 4-Methoxyaniline see Anisidine 4-Methoxybenzaldehyde see Anisaldehyde Methoxybenzaldehyde derivatives 72 Methoxycinnamic acid 277... 

Mercury nitrate, corrosive sublimate, white arsenic, and lead acetate are occasionally used as reagents, and soap is described as an indication of hard waters, as when added to them a decomposition takes place, the acid unites with alkali, and the oil is disengaged such waters as these are generally called hard waters, and are unfit for washing cloaths, as also for boiling pulse and the harder kinds of flesh. 18 The list of qualitative reagents for the many constituents of natural waters comprises the principal reagents in use at present. 

Filter paper moistened with mercury(I) nitrate solution may also be used this is blackened by ammonia. The mercury(I) nitrate reagent contains an excess of free nitric acid it is advisable, therefore, to add sodium carbonate solution dropwise and with stirring to about 1 ml of mercury(I) nitrate solution until a slight permanent precipitate is produced. The solution is centrifuged and the centrifugate is employed for the preparation of mercury(I) nitrate paper. ... 

Recently, Hong and Zhou [48] worked out an automatic analytical technique based on the mercury(II) thiocyanate, iron(III) nitrate reagent. The fully automated apparatus uses the continuous-flow injection principle. A sample of 20 xL is injected into the water carrier stream, which merges with the reagent stream containing mercury(II) thiocyanate, iron(III) nitrate polyoxyethylene glycol dodecyl ether in aqueous methanol. After it passes through the reactor section, the absorbance is measured at 480 nm. 

Mercurous Nitrate. Mercurous nitrate [10415-75-5] Hg2N20 or Hg2(N02)2, is a white monoclinic crystalline compound that is not very soluble in water but hydrolyzes to form a basic, yellow hydrate. This material is, however, soluble in cold, dilute nitric acid, and a solution is used as starting material for other water-insoluble mercurous salts. Mercurous nitrate is difficult to obtain in the pure state directly because some mercuric nitrate formation is almost unavoidable. When mercury is dissolved in hot dilute nitric acid, technical mercurous nitrate crystallizes on cooling. The use of excess mercury is helpful in reducing mercuric content, but an additional separation step is necessary. More concentrated nitric acid solutions should be avoided because these oxidize the mercurous to mercuric salt. Reagent-grade material is obtained by recrystaUization from dilute nitric acid in the presence of excess mercury. 

Discussion. Potassium may be precipitated with excess of sodium tetraphenyl-borate solution as potassium tetraphenylborate. The excess of reagent is determined by titration with mercury(II) nitrate solution. The indicator consists of a mixture of iron(III) nitrate and dilute sodium thiocyanate solution. The end-point is revealed by the decolorisation of the iron(III)-thiocyanate complex due to the formation of the colourless mercury(II) thiocyanate. The reaction between mercury( II) nitrate and sodium tetraphenylborate under the experimental conditions used is not quite stoichiometric hence it is necessary to determine the volume in mL of Hg(N03)2 solution equivalent to 1 mL of a NaB(C6H5)4 solution. Halides must be absent. 

Reaction to Ammonium Ion (Nessler s Reagent). Introduce 5 ml of a 0.1 N mercury(II) nitrate solution heated to 80 °C into a 50-ml beaker and add 5 ml of a 0.1 A potassium iodide solution. Cool the mixture, let the precipitate settle, pour off the solution, and wash the precipitate three times with cold water by decantation. Add 0.2 g of potassium iodide dissolved in 5 ml of water to the precipitate. When the latter dissolves, pour in 3 ml of a 10% sodium hydroxide solution and transfer the contents into a dark jar. 

Other reagents that convert benzylic halides to aldehydes are 2-nitropropane-NaOEt in EtOH,336 mercury(I) nitrate followed by ethanolic alkali,337 and pyridine followed by p-nitrosodimethylaniline and then water. The last procedure is called the Krohnke reaction. Primary halides in general have been oxidized to aldehydes by trimethylamine oxide,338 by... 

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