Bismuth amalgam

The most powerful reductant is therefore zinc amalgam, whilst bismuth amalgam is the least reducing. The final reduction products obtained with these amalgams for a few elements are collected in Table 10.10. 

Peter LM, Wright GA (1987) Electrochemical kinetics of bismuth sulphide formation on bismuth amalgam. Electrochim Acta 32 1353-1356... 

Pertechnetate forms a blue complex and perrhenate a brownish-yellow complex with K4[Fe(CN) ] in presence of bismuth amalgam. This permits the spectrophotometric determination of both elements in the same solution . The adsorption maxima of the technetium and rhenium complexes are at 680 and 420 nm, respectively. The molar extinction coefficients are 10,800 for technetium and 4,000 for rhenium. Metals forming color or precipitates with K4[Fe(CN) ] must first be removed. 

Procedure To 5.7 M hydrochloric acid (2 ml) are added the test solution containing Tc04T, bismuth amalgam and a 5% aqueous solution of K4[Fe(CN)fe]. 

Bismuth amalgamates with mercury which the regulus of cobalt does not do at all. 

Reduction of add solutions of vanadium pentoxide to the tetravalent state also takes place with bismuth amalgam 5 magnesium gives the trivalent salts of vanadium, while by using zinc, zinc coated with cadmium, electrolytically deposited cadmium, or sodium amalgam in the absence of air, divalent vanadium salts are obtained in solution.7 Vanadous salts and hypovanadous salts are, however, much more conveniently prepared by electrolytic reduction of acid solutions of vanadium pentoxide in an atmosphere of carbon dioxide.8... 

The following data were obtained in a study of the vapor pressure of mercury (pi) in equilibrium with bismuth amalgams at 321° C ... 

What would be the b.m.f. at 321° C of a cell consisting of two bismuth amalgam electrodes, with mole fractions 0.1 and 0.9 of bismuth, respectively, in the same electrolyte (Use results of Exercise 6.)... 

A potentiometric method using a bismuth amalgam electrode has been used to determine formation constants of mixed chloride-nitrate complexes of Bi at 298 K. Complex composition was determined by the Sillen method, and the stability constants of BiCl (N03)m " compounds are given at zero ionic strength. ... 

Spcctrophotometric studies on technetium and rhenium were carried out with K4[b e(C N)f,], sulphosalicylic acid, and a-picolinic acid using pcrtechnetatc or perrhe-nate as starting compounds and bismuth amalgam, SnCl2 or ascorbic acid as reducing agents 78j. 

ZINC, CADMIUM, TIN, LEAD AND BISMUTH AMALGAMS (UQUID)... 

Silver may also be determined by coulometric dissolution of silver deposits (210) or by spontaneous electrolysis against a bismuth amalgam anode (215). The oxidation of silver (I) to silver (II) at solid anodes is well known but is not suitable for direct coulometric purposes owing to the rapid reaction of silver (II) with... 

Batteries. Many batteries intended for household use contain mercury or mercury compounds. In the form of red mercuric oxide [21908-53-2] mercury is the cathode material in the mercury—cadmium, mercury—indium—bismuth, and mercury—zinc batteries. In all other mercury batteries, the mercury is amalgamated with the zinc [7440-66-6] anode to deter corrosion and inhibit hydrogen build-up that can cause cell mpture and fire. Discarded batteries represent a primary source of mercury for release into the environment. This industry has been under intense pressure to reduce the amounts of mercury in batteries. Although battery sales have increased greatly, the battery industry has aimounced that reduction in mercury content of batteries has been made and further reductions are expected (3). In fact, by 1992, the battery industry had lowered the mercury content of batteries to 0.025 wt % (3). Use of mercury in film pack batteries for instant cameras was reportedly discontinued in 1988 (3). 

Amalgamated zinc powder has been used as the negative material to prevent zinc corrosion and zinc passivation. Recently, from the viewpoint of environmental problems, mercury-free alkaline-manganese batteries were developed by using zinc powder with indium, bismuth and other additives [2-4]. Adding indium to zinc powder is the most effective way to improve the characteristics of the cells [3]. Figure 3 shows the variation in the internal impedance of the cells according to the additive content of the zinc powder. 

A modification of the electrolytic method involves the electrolysis of solutions containing both the metallic and the mercuric ions. This procedure should possibly lead to the deposition of amalgams of varying composition, but no extensive study of this sort has ever been reported. Bismuth and copper amalgams have been prepared in this manner. 

Liquid amalgams For the liquid amalgams of zinc, cadmium, lead, and bismuth, the potentials do not differ widely from those of solid metals, for the following reasons. ° ° If solid metal is added to mercury, a solid phase eventually is formed, and at equilibrium both phases of the saturated, two-phase amalgam must have the same electrode potential. The emf of the cell... 

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