Displacement series

Eor example, beryUium occurs at the bottom of a displacement series with NTA allowing this metal to be recovered as the hydroxide by pH adjustment of an ore processing solution all of the interfering metals remain sequestered by chelation (14). Additionally, because other metals present caimot displace iron in an iron—EHPG chelate, the chelate can be used in highly calcareous soils to supply iron as a trace nutrient in agriculture (15). 

ACTIVITY SERIES- Also referred to as the electromotive series or the displacement series, this is an arrangement of the metals (other elements can be included) in the order of their tendency to react with water and acids, so that each metal displaces from solution those below itiu the series and is displaced by those above it. See Table 1. Since the electrode potential of a metal in equilibrium with a solution of its ions cannot be measured directly, the values in the activity series are, in each case, the difference between the electrode potential of the given metal tor element) in equilibrium with a solution of its ions, and that of hydrogen in equilibrium with a solution of its ions. Thus in the table, it will be noted that hydrogen lias a value of 0.000. In experimental procedure, the hydrogen electrode is used as the standard with which the electrode potentials of other substances are compared. The theory of displacement plays a major role in electrochemistry and corrosion engineering. See also Corrosion and Electrochemistry. 

Table 16.1 shows the displacement series for ion exchange materials. When an ion species high in the table is in solntion, it can displace ion species in the insoluble material below it in the table and, thus, be removed from solution. As noted in this table, to remove any cation in solution, the displaceable cation must be the proton H and to remove any anion, the displaceable anion must be the hydroxyl ion OIT. 

Displacement series—A table of ions indicating that ions at the top of the table can displace ions below them in the table. 

Name Interlayer formula Perovskite layer formula Perovskite slab orientation Perovskite slab displacement Series formula Examples... 

FIGURE 14 The dependence of reaction rate constant - Pi on effective GammeFs constant Dov in logarithmic coordinates, obtained by straight line displacement (series 2)... 

Machine runs for the MDI flexible moulded foam were conducted on a Krauss-Maffei, cylinder displacement series, high pressure machine. Fresh premixes, consisting of the appropriate polyols, water, crosslinker, surfactants and catalysts for each formulation were charged to the machine. Modified MDI was used throughout the entire study. All chemical temperatures were held at 25 °C 2 °C via the machine s internal temperature control units. Foam pours were made into an isothermally controlled heated aluminium mould maintained at 60 °C 2 °C. The mould was a typical physical property tool designed with... 

As with the electromotive series, there are really many displacement series, according to the kind of system (aqueous solution, molten chloride, etc.) in which the displacement is occurring. 

Note that the electromotive series is an affinity series for the formation of compounds in solution. Likewise the displacement series. 

The contact series, the various electromotive series, the displacement series, and the various affinity series turn out to be remaikably similar to each other. Though by no means all identical, their similarities sufficiently outweigh their differences to encourage the formation of a single series as an approximate expression of all of them. This series is called the electrochemical series. 

Et. The variation in for the H atom displacement series is rather marked and may be a consequence of different Eq values for the series of reactions. 

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