Mercury acidity

The white precipitate which forms is filtered and dried at 80°C, yielding 45 g of chloro-mercuri acid (= 89% of the theory), MP 106° to 109°C (decomp.). This compound is finally obtained in analytically pure form and with a constant melting point by two recrystallizations from acetone-water giving a MP of 131° to 132°C with decomposition. 

C NrOH-tHg(ONCjj Fulininie Mercury acid fulminate... 

Plates of copper or zinc precipitate colloidal silver from solution.10 The solid forms are brittle, and amalgamate with mercury. Acids convert them into grey silver, without evolution of gas. 

Sulphuric (Sulphate of Sulphurous Mercury. Acid. Mercury). Anhydride. Water. 

In spite of the large quantities of sulfuric add offered, a weD-defined demand exists for add of special purity. This means low mercury acid with 0.1 ppmw Hg is at a premium (5 DM per tonne in 1994) over typical merchant-grade product, which has up to 0,5 ppmw mercury jll]. A specification for technical-grade sulfuric acid is given in Table 11.8. 

Note It may be necessary to add water, one drop at a time, to the mercury-acid solution in order to start reaction. 

Identification and category of the waste. For example, list a waste as cyanide, mercury, acid, and so forth. If the waste contains more than one type of chemical, list all known components of the waste. 

Prepared by condensing p-chlorophenol with phlhalic anhydride in sulphuric acid solution in the presence of boric acid. The chlorine atom is replaced by hydroxyl during the condensation. It can also be prepared by oxidation of anthraquinone or 1-hydroxyanthraquinone by means of sulphuric acid in the presence of mercury(ll) sulphate and boric acid. 

There is a fair amount of work reported with films at the mercury-air interface. Rice and co-workers [107] used grazing incidence x-ray diffraction to determine that a crystalline stearic acid monolayer induces order in the Hg substrate. Quinone derivatives spread at the mercury-n-hexane interface form crystalline structures governed primarily by hydrogen bonding interactions [108]. 

In presence of hydrochloric acid, tin(II) in aqueous solution (1) is precipitated by hydrogen sulphide as brown SnS, and (2) will reduce mercury(II) chloride first to mercury(I) chloride (white precipitate) and then to metallic mercury. 

Tin(IV) in aqueous acid gives a yellow precipitate with hydrogen sulphide, and no reaction with mercury(II) chloride. 

The more noble metals (for example copper, mercury and silver) can form oxides, and exhibit variable oxidation state in such compounds (for example CU2O, CuO), but it is not easy to prepare such oxides by direct action of oxygen on the metal, and elevated temperatures are necessary. Moreover, in the case of silver and mercury, loss of oxygen from the oxide by heating is easy. The oxidesare, however, basic (for example Ag20 - Ag, CuO - Cu in acids). 

The gas is dried by passage through concentrated sulphuric acid and collected over mercury. 

Properties—Hydrogen iodide is a colourless gas. It is very soluble in water and fumes in moist air (cf. hydrogen chloride), to give hydriodic acid. Its solution forms a constant boiling mixture (cf. hydrochloric and hydrobromic acids). Because it attacks mercury so readily, hydrogen iodide is difficult to study as a gas, but the dissociation equilibrium has been investigated. 

Halogens can act as ligands and are commonly found in complex ions the ability of fluorine to form stable complex ions with elements in high oxidation states has already been discussed (p. 316). However, the chlorides of silver, lead(Il) and mercury(l) are worthy of note. These chlorides are insoluble in water and used as a test for the metal, but all dissolve in concentrated hydrochloric acid when the complex chlorides are produced, i.e. [AgCl2] , [PbC ] and [Hg Clj]", in the latter case the mercury(I) chloride having also disproportionated. 

Despite its electrode potential (p. 98), very pure zinc has little or no reaction with dilute acids. If impurities are present, local electrochemical cells are set up (cf the rusting of iron. p. 398) and the zinc reacts readily evolving hydrogen. Amalgamation of zinc with mercury reduces the reactivity by giving uniformity to the surface. Very pure zinc reacts readily with dilute acids if previously coated with copper by adding copper(II) sulphate ... 

The metal is slowly oxidised by air at its boiling point, to give red mercury(II) oxide it is attacked by the halogens (which cannoi therefore be collected over mercury) and by nitric acid. (The reactivity of mercury towards acids is further considered on pp. 436, 438.) It forms amalgams—liquid or solid—with many other metals these find uses as reducing agents (for example with sodium, zinc) and as dental fillings (for example with silver, tin or copper). 

Hence mercury is a poor reducing agent it is unlikely to be attacked by acids unless these have oxidising properties (for example nitric acid), or unless the acid anion has the power to form complexes with one or both mercury cations or Hg]", so altering the... 

E values. Nitric acid attacks mercury, oxidising it to Hg (aq) when the acid is concentrated and in excess, and to Hgf (aq) when mercury is in excess and the acid dilute. Hydriodic acid Hl(aq) attacks mercury, because mercury(Il) readily forms iodo-complexes (see below, p. 438). 

Mercury(I) ions can be produced in solution by dissolving excess mercury in dilute nitric acid ... 

Hg -F 8H-" -F 2N03" 3Hgi+ -F 2NO -F 4H2O From the acid solution white hydrated mercury(I) nitrate Hg2(N03)2.2H20 can be crystallised out this contains the ion... 

Mercuryill) chloride is obtained in solution by dissolving mercury(II) oxide in hydrochloric acid the white solid is obtained as a sublimate by heating mercury(II) sulphate and solid sodium chloride ... 

Mercuryill) sulphate and nitrate are each obtained by dissolving mercury in the appropriate hot concentrated acid the sulphate is used as a catalyst (p,436),... 

Acid amides have weakly amphoteric properties, and thus give salts such as CjHsCONHj.HCl with strong acids, and salts of the type C HsCONHNa with strong bases. These compounds have to be prepared at low temperatures to avoid hydrolysis, and are difficult to isolate. The mercury derivatives can, however, usually be readily prepared, because mercuric oxide is too feebly basic to cause hydrolysis of the amide, and the heavy mercuric derivatives crystallise well. 

A 1500 ml. flask is fitted (preferably by means of a three-necked adaptor) with a rubber-sleeved or mercury-sealed stirrer (Fig. 20, p. 39), a reflux water-condenser, and a dropping-funnel cf. Fig. 23(c), p. 45, in which only a two-necked adaptor is shown or Fig. 23(G)). The dried zinc powder (20 g.) is placed in the flask, and a solution of 28 ml. of ethyl bromoacetate and 32 ml. of benzaldehyde in 40 ml. of dry benzene containing 5 ml. of dry ether is placed in the dropping-funnel. Approximately 10 ml. of this solution is run on to the zinc powder, and the mixture allowed to remain unstirred until (usually within a few minutes) a vigorous reaction occurs. (If no reaction occurs, warm the mixture on the water-bath until the reaction starts.) The stirrer is now started, and the rest of the solution allowed to run in drop-wise over a period of about 30 minutes so that the initial reaction is steadily maintained. The flask is then heated on a water-bath for 30 minutes with continuous stirring, and is then cooled in an ice-water bath. The well-stirred product is then hydrolysed by the addition of 120 ml. of 10% sulphuric acid. The mixture is transferred to a separating-funnel, the lower aqueous layer discarded, and the upper benzene layer then... 

Fit a three necked 250 ml. flask with a central rubber-sleeved or mercury-sealed stirrer, c/. Fig. 23(c), p. 45, where only two necks are shown, and with a thermometer the bulb of which reaches as near the bottom of the flask as the stirrer allows the third neck will carry at first a dropping-funnel and later a reflux condenser. Place 20 g. (19-5 ml.) of ethyl acetoacetate and 45 ml. of glacial acetic acid in the flask and by ice-water cooling adjust the temperature of the stirred mixture to 5 -7° maintain this temperature whilst adding a solution of 5 4 g. of sodium nitrite in 8 ml. of water slowly from the dropping-funnel during 15 minutes. Continue the stirring for 20-30 minutes, and then... 

Mercuric chloride test. Add mercuric chloride solution to formic acid or a solution of formate and w arm. A white precipitate of mercurous chloride, insoluble in dil. HCl, is produced. Sometimes the reduction proceeds as far as metallic mercury, which appears as a grey precipitate. 

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