Sulphate mercurous

The analytical reagent grade is suitable for most purposes. The commercial substance may be purifled by shaking for 3 hours with three portions of potassium permanganate solution (5 g. per litre), twice for 6 hours with mercury, and Anally with a solution of mercuric sulphate (2-5 g. per litre). It is then dried over anhydrous calcium chloride, and fractionated from a water bath at 55-65°. The pure compound boils at 46-5°/760 mm. 

Much of the acetaldehyde of commerce is obtained by the hydration of acetylene in hot dilute sulphuric acid solution in the presence of mercuric sulphate as catalyst ... 

The first reaction may be carried out either in the liquid or vapour phase although the liquid phase route is now commercially obsolete. In a typical liquid phase preparation, acetylene is passed through an agitated solution of glacial acetic acid and acetic anhydride containing mercuric sulphate, preferably formed in situ, in a finely divided state as catalyst. 

Ten c.c. of the neutral solution of the potassium salt is shaken with 1 to 1 5 grams lead peroxide 2 c.c. of a solution of mercuric sulphate is added (prepared by dissolving 5 grams HgO in 20 c.c. concentrated HcSO and water to 100 c.c.). The solution is filtered and a 2 per cent. 

However, in the case of stress-corrosion cracking of mild steel in some solutions, the potential band within which cracking occurs can be very narrow and an accurately known reference potential is required. A reference half cell of the calomel or mercury/mercurous sulphate type is therefore used with a liquid/liquid junction to separate the half-cell support electrolyte from the process fluid. The connections from the plant equipment and reference electrode are made to an impedance converter which ensures that only tiny currents flow in the circuit, thus causing the minimum polarisation of the reference electrode. The signal is then amplifled and displayed on a digital voltmeter or recorder. 

Mercury/mercurous sulphate (Hg/HgSOj, SOJ ) Silver/silver chloride (Ag/AgCl, Cl )... 

This effect appears to be of importance in the case of normal galvanic cells, the electromotive forces of which depend on the concentration of solutions in equilibrium with depolarising solids such as calomel or mercurous sulphate. The exact relationships are, unfortunately, not yet wholly elucidated. 

Mercury Mercuric iodide Mercuric nitrate Mercuric oxide Mercurous nitrate Mercuric sulphate Mercuric sulphide Mercurous sulphate... 

The described electrodes, and especially the silver chloride, calomel and mercurous sulphate electrodes are used as reference electrodes combined with a suitable indicator electrode. The calomel electrode is used most frequently, as it has a constant, well-reproducible potential. It is employed in variously shaped vessels and with various KC1 concentrations. Mostly a concentration of KC1 of 0.1 mol dm-3, 1 mol dm-3 or a saturated solution is used (in the latter case, a salt bridge need not be employed) sometimes 3.5 mol dm-3 KC1 is also employed. The potentials of these calomel electrodes at 25°C are as follows (according to B. E. Conway) ... 

The mostly used Weston cell consists of mercurous sulphate and cadmium amalgam electrodes ... 

The separation of cystine and tyrosine as they are obtained by hydrolysis with hydrochloric acid was described by Morner in I901. The protein—hair, keratin from horn, eggshells, etc.—was boiled with five times its quantity of 13 per cent hydrochloric acid under a reflux condenser on a water bath for six to seven days. The solution was then decolorised with charcoal and evaporated in vacuo, and the residue dissolved in 60 to 70 per cent, alcohol. The two acids then crystallised out on neutralising with soda, and were separated by fractional crystallisation from ammonia if much tyrosine was present it separated out first, but if cystine exceeded tyrosine in quantity this compound crystallised out first the remainder was only separated with difficulty. Embden separated the mixture of the two acids by means of very dilute nitric acid, in which tyrosine is very easily soluble, but cystine with difficulty. Their separation may also be effected by precipitation with mercuric sulphate in 5 per cent, sulphuric acid solution in which the mercury compound of tyrosine is soluble (Hopkins and Cole). 

The isolation of tryptophane by Hopkins and Cole in 1902 from the mixture of products formed by the tryptic digestion of caseinogen by precipitation in sulphuric acid solution with mercuric sulphate, besides adding to our list of foundation-stones or units of the protein molecule, gave us the explanation of three phenomena long known in connection with the chemistry of the proteins, namely (i) of the reddish-... 

The interfacial tensions of a number of aqueous solutions against mercury have been measured by McLewis, Patrick and others. The tension was lowered by addition of all the solutes examined, including mercurous sulphate, salicylic acid, picric acid, neofuchsin, morphine hydrochloride, caffeine, aniline, sodium glycocholate. All of these substances except mercurous sulphate lower the surface See p. 36. 

Although there exists a concentration gradient of mercurous sulphate from the anode to the cathode it is unlikely that this causes an appreciable alteration in the electrical potential throughout the bulk of the electrolyte. Hence without serious error the applied E.M.F. V may be equated to the difference in the values of V at the two electrodes and since F at the unpolarisable electrode remains unaltered the variation of a with V is observed at the cathode. With the aid of thermo-dynamic reasoning, Lippmann deduced the relation... 

If when a metal comes into contact with an electrolyte, e.g. mercury in contact with dilute sulphuric acid containing mercurous sulphate it is not at the electrical potential necessary for equilibrium the thermodynamic potential of the metallic ions in the two phases will differ and consequently some of them will pass across the boundary or compensating adjustment of the surface will take place. 

Dargan PI et al Case report Severe mercuric sulphate poisoning treated with 2,3-dimercaptopropane-l-sulphonate and haemodiafiltration. Crit Care 2003 7 Rl. 

A convenient method for the laboratory preparation of sulphuryl chloride consists in boiling chlorosulphonic acid with about one per cent, of mercury or mercuric sulphate under a reflux condenser kept at a temperature of 70° C. in order to return to the flask any unchanged chlorosulphonic acid ... 

With excess of mercuric oxide, mercuric sulphate is also formed.1 Selenium is attacked rapidly by sulphuryl chloride ... 

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