Silver tartrate

Silver is incompatible with oxalic or tartaric acids, since the silver salts decompose on heating. Silver oxalate explodes at 140°C, and silver tartrate loses carbon dioxide. 

Similar active salts are prepared through tartaric acid, in which case a solution of the chloride is treated with silver tartrate. 

When sample is heated, the evolution of carbon monoxide, carbon dioxide, and sulfur dioxide (burnt sugar odor) results White precipitate of silver tartrate... 

Silver nitrate solution white, curdy precipitate of silver tartrate, Ag2. C4H4Oe, from neutral solutions of tartrates, soluble in excess of the tartrate solution, in dilute ammonia solution and in dilute nitric acid. On warming the ammoniacal solution, metallic silver is precipitated this can be deposited in the form of a mirror under suitable conditions. 

SAFETY PROFILE Moderately toxic by intravenous route. Mildly toxic by ingestion. Reaction with silver produces the unstable silver tartrate. When heated to decomposition it emits acrid smoke and irritating fumes. 

Stoichiometric quantities of AgNO 3 and potassium sodium tartrate (Rochelle salt) are dissolved in water and the solutions combined. On addition of alcohol (in which silver tartrate is insoluble), the product precipitates as a white, cheeselike deposit which is immediately filtered through a suction or Buchner filter. The precipitate is washed with aqueous alcohol until no further Ag+ ion is detectable. Further purification may be achieved by crystallization from 80°C water, a small quantity of AgsO being formed in the process. The aqueous solution is filtered and alcohol is again added. The precipitate is filtered, washed first with aqueous, then with absolute alcohol or acetone, and dried in vacuum over H3SO4. 

Alternate method A hot, moderately cone, solution of Rochelle salt is added to an 80°C dilute solution of AgNOs the reaction (addition) is complete when the continually forming precipitate no longer dissolves. The silver tartrate crystallizes on cooling in the form of fine flakes which acquire a white, metallic sheen on washing. 

A solution of 100 g. of [Co en3]Brs in water is treated with the amount of silver tartrate (68.3 g.) needed for reaction with two atoms of bromine. After boiling, the AgBr precipitate is filtered off and then washed with boiling water until the water is no longer yellow. The filtrate and washings are combined and... 

Silver tartrate explosive mixtures Silver tetrazene... 

Reduction of ammoniacal silver nitrate. Add i drop of dil. NaOH solution to about 5 ml. of AgNO, solution, and add dil. NH solution drop by drop until the silver oxide is almost redissolved. Add AgNO, solution until a faint but permanent precipitate is obtained (see p.525). Then add 0 5 ml. of a neutral tartrate solution. Place the tube in warm water a silver mirror is formed in a few minutes. 

Formation of silver mirror or precipitate of silver indicates reducing agent. (This is often a more sensitive test than I (a) above, and some compounds reduce ammoniacal silver nitrate but are without effect on Fehling s solution.) Given by aldehydes and chloral hydrate formates, lactates and tartrates reducing sugars benzoquinone many amines uric acid. 

H. 8-Hydroxyquinaldine (XI). The reactions of 8-hydroxyquinaldine are, in general, similar to 8-hydroxyquinoline described under (C) above, but unlike the latter it does not produce an insoluble complex with aluminium. In acetic acid-acetate solution precipitates are formed with bismuth, cadmium, copper, iron(II) and iron(III), chromium, manganese, nickel, silver, zinc, titanium (Ti02 + ), molybdate, tungstate, and vanadate. The same ions are precipitated in ammoniacal solution with the exception of molybdate, tungstate, and vanadate, but with the addition of lead, calcium, strontium, and magnesium aluminium is not precipitated, but tartrate must be added to prevent the separation of aluminium hydroxide. 

Sulphuric acid is not recommended, because sulphate ions have a certain tendency to form complexes with iron(III) ions. Silver, copper, nickel, cobalt, titanium, uranium, molybdenum, mercury (>lgL-1), zinc, cadmium, and bismuth interfere. Mercury(I) and tin(II) salts, if present, should be converted into the mercury(II) and tin(IV) salts, otherwise the colour is destroyed. Phosphates, arsenates, fluorides, oxalates, and tartrates interfere, since they form fairly stable complexes with iron(III) ions the influence of phosphates and arsenates is reduced by the presence of a comparatively high concentration of acid. 

Additional Exercises Crystals of silver sulfate, silver chromate, calcium tartrate, and copper tartrate. 

The essential distinction between this and ordinary inks is the use of tartrate instead of nitrate of silver. 

The first of these, which may be used with stsel pens, and which is most readily developed on tho application of heat, is prepared in the subjoined manner — Nitrate of silver is triturated iu a mortar with an equivalent of dasiccated tartoric acid. Water is then added, which causes the. separation of crystals of tartrate of silver, nitric acid being set free. The latter is neutralized carefully by adding ammonia, which also dissolves the metallic tartrate. Gum, tinctorial matter, and water arc subsequently added in quantities which may he varied at pleasure. 

By this process, remarks the patentee, the nitric acid, which is essential to a good marking bile, is retained, and the tartrate of silver formed is soluble in half tho quantity of ammonia ordinarily required when nitrate of silver is the basis of the ink. 

Tartrate of Silver.—2 AgO, CflII40ig—by mixing neutral tartrate of potash or Rochelle salt with nitrate of silver, A white, crystalline, lustrous powder gently heated, spongy silver remains, with evolution of pyro-tartnric and carbonic acids. 

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