Salts chloride, decomposition potential

The decomposition potentials of rare metal chlorides and fluorides are generally lower than the corresponding salts of the alkali or alkaline earth metals. It is necessary that the decomposition potential at unit activity of the salt being electrolysed is substantially less than that of the other inert salts present. A large difference in the two potentials at unit activity allows an adequate margin of potential when the activity of the salt being electrolysed falls, e.g. at the end of a batch electrolysis period when the rare metal salt concentration is low. 

Sm VSm Transformation in Chloride Melts Stability of samarium ions (Sm % Sm " ) in the alkaline chloride melts changes as functions of the solvent salt cations and temperature [4]. Sm " exhibits a higher stability for a larger solvent salt cation and lower temperature. Electrochemical reduction of Sm " into Sm in KQ-NaCl-CsCl melt at an inert cathode has been found to occur in two steps as shown in Eqs. 12 and 13. And the reduction of Sm " to Sm° takes place at near the decomposition potential of the supporting electrolyte. In addition, Sm " losing one electron to form Sm " takes place at the anode in terms of reaction Eq. 14, making Sm " Sm /transformation at the electrodes therefore, this process can circulate in the cathode and anode, and therefore nearly no Sm metal can be obtained at the cathode, resulting an extremely low current efficiency. This is the rea-sOTi why samarium caimot be produced from the chloride melts by molten salt electrolysis. It is reported that when the concentration of Sm " ions reach 0.1 wt% in the chloride melts, the current efficiency will be substantially decreased. Eu " behaves in nearly the same manner as Sm " in the chloride melts. 

Perchloric acid is an extremely strong acid in aqueous solution (see Table 7.3). Although [ 104] (Fig. 17.12b) does form complexes with metal cations, the tendency to do so is less than for other common anions. Consequently, NaC104 solution is a standard medium for the investigation of ionic equilibria in aqueous systems, e.g. it is used as a supporting electrolyte in electrochemical experiments (see Box 8.2). Alkali metal perchlorates can be obtained by disproportionation of chlorates (eq. 17.76) under carefully controlled conditions traces of impurities can catalyse decomposition to chloride and O2. Perchlorate salts are potentially explosive and must be handled with particular care. For example, solid NH4CIO4 decomposes at 298 K according to eq. 17.79, and mixtures of ammonium perchlorate and aluminium are standard missile propellants. 

The Electrolysis of Molten Sodium Chloride. Molten sodium chloride (the salt melts at 801° C) conducts an electric current, as do other molten salts. During the process of conducting the current a chemical reaction occurs—the salt is decomposed. If two electrodes (carbon rods) are dipped into a crucible containing molten sodium chloride and an electric potential (from a battery or generator) is applied, metallic sodium is produced at the negative electrode—the cathode—and chlorine gas at the positive electrode—the anode. Such electrical decomposition of a substance is called electrolysis. 

It is known that the products of electrochemical decomposition of fluoroborate salts contain fluorinated compounds [12], which are enviroirnientaUy harmful. That is why the azide compound, BMMIiiiNa, is considered as a potentially environmental friendlier electrolyte. The electrochemical reduction of TiCU solutions in BMMImNs IL at 65 °C which is about 20 °C higher than the melting point of the IL has been studied in [8]. This salt was synthesised using the reaction of l-butyl-2,3-dimethyl imidazolium chloride with sodium azide in acetone ... 

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