Equivalent conductance bromide

This study was undertaken to determine whether or not the electrolytic conductance of the lithium bromide-bromosuccinic acid-acetone system can be described by the Fuoss-Onsager-Skinner equation (FOS equation)—Equation 2—by treating the system as lithium bromide in a mixed solvent, and to establish values for Ao and KA for lithium bromide in anhydrous acetone with the same equation. The equation requires knowledge of the concentration and corresponding equivalent conductance along with the dielectric constant and viscosity of the solvent and the temperature that is,... 

A value for the equivalent conductance at infinite dilution for lithium bromide in acetone was first calculated in 1905 by Dutoit and Levier (13) for 18°C 166 12 1 cm2 eq-1. A graphical method involving Ostwald s dilution law (A-1 = Ao-1 + cA/KdAq2), applied to their data in 1913 by Kraus and Bray (14), produced values of 5.7 X 10 4 for Kd and 165 12 1 cm2 eq-1 for Aq. Deviations from the mass action law (nonlinearity in the graph) become appreciable at concentrations of ca. 10 3N. Both groups pointed out that measurements in acetone are liable to error from several sources, including the presence of solvent impurities and exposure to light. A solvent correction of 21% was applied to their most dilute solution. 

Reynolds and Kraus (17) obtained conductance for 14 salts in acetone at 25°C, and used the Fuoss method to calculate their equivalent conductances at infinite dilution. Among the salts were tetra-n-butylammonium fluorotri-phenylborate, tetra-n-butylammonium picrate, lithium picrate, and tetra-n-butylammonium bromide. They then derived ionic equivalent conductances at infinite dilution by the method of Fowler (18) using tetra-n-butylammonium fluorotriphenylborate as the reference electrolyte and obtained a value of 188.7 12 1 cm2 eq-1 for Aq for lithium bromide. 

The experimental results are summarized for each series (the series numbers correspond to the respective solvent numbers) in Table I. The first column is simply for reference, and the second is the normality of the lithium bromide. The third column gives the experimental equivalent conductance as calculated from the corrected specific conductances. 

Table I shows that y decreases with increasing concentration of lithium bromide for each series, but that the decrease becomes smaller as the bromosuccinic acid concentration gets larger. The effect of lithium bromide and bromosuccinic acid concentration on y is also demonstrated in Figure 1. All the terms listed in Table I diminish the equivalent conductance from Aq for Series II-IV and the magnitude of the reduction for each term increases with increasing...

If the system behaved ideally, the specific conductances should be additive. Figure 7 shows the specific conductance of the solution corrected (by subtraction) for the specific conductances of the acetone and lithium bromide for various fixed amounts of lithium bromide as a function of bromosuccinic acid concentration. Inasmuch as this should be equal to the equivalent conductance of bromosuccinic acid, if there were no interaction among the conducting species all four curves should coincide with the curve for no lithium bromide. Clearly, some type of interaction must occur. 

In dilute solution the rare earth salts behave as 1 3 electrolytes and obey the Onsager equation in a modified form up to a concentration of 0.01 N. The behaviour of various rare earth salts, such as chlorides, bromides, nitrates and perchlorates has been examined [209—212]. The equivalent conductivity data for the rare earths is compiled in Table 11. Extensive ion-pair formation has been observed for rare earth sulphate solutions. 

Continued elution with Na+OH" causes the sample ions to leave the column and pass through a small detector cell. If a conductivity detector is used, the conductance of all of the anions, plus that of the cations (Na+ in this example) will contribute to the total conductance. If the total ionic concentration remains constant, how can a signal be obtained when a sample anion zone passes through the detector The answer is that the equivalent conductance of chloride (76 ohm cm equiv" ) and bromide (78) is much lower than that of OH" (198). The net result is a decrease in the conductance measured when the chloride and bromide zones pass through the detector. 

Fig. 8. Equivalent conductivity of cetyl pyridine bromide (A), cetyl pyridine p) and bromide (A ). After the critical concentration Ap increases (association), while exhibits negative values (the Br ions are carried along with the micelles). From Harthley 1939.

In the same year as Arrhenius, Bouty" published conductivities of very dilute solutions of salts, acids, and bases (see p. 670). He thought the equivalent conductivities of all salts at very high dilutions were equal (which is only approximately true). Acids and bases gave different results, which he explained by assuming hydration, and (like Arrhenius) he thought that conductivity is due to combination with water. He found that solutions of mercuric chloride, bromide, and cyanide were not condueting. 

The cmc and micelle ionization degrees near the cmc (9) were determined by emf measurements using a specific bromide ion electrode (Orion 9435), in conjunction with a double junction reference electrode (Orion 9002) and a millivoltmeter (Orion 701A). Some determinations were also performed by means of conductivity. It was noted that emf measurements yielded cmc values slightly lower than those obtained from the equivalent conductivity vs. (concentration) plots. This, however, is of no importance in this work where we are only interested in relative changes. 

When direct detection is used, the eluent anion has a significantiy lower equivalent conductance than the sample ions to be detected. As an example, a benzoate salt (limiting equivalent conductance = 32 S cm equiv ) can be used for direct detection of ions such as chloride, bromide, iodide, nitrate and sulfate, which have a limiting equivalent conductance between 71 and 80 S cm equiv . A significant increase in overall conductivity is obtained as each of the sample ions passes through the detector, provided that the eluent concentration is not too high. 

They react with a solution of bromine in carbon tetrachloride by substitution and an equivalent quantity of hydrogen bromide is evolved (compare addition with unsaturated compounds). When the test is conducted with bromine water and a dilute aqueous solution of a phmiol, the sim of reaction is the separation of a sparingly soluble bromine substitution product. ... 

A somewhat related microwave-promoted 5 -0-allylation of thymidine has been described by the Zerrouki group (Scheme 6.108) [215], While the classical method for the preparation of 5 -0-allylthymidine required various protection steps (four synthetic steps in total), the authors attempted the direct allylation of thymidine under basic conditions. Employing sodium hydride as a base at room temperature in N,N-dimethylformamide resulted in the formation of per-allylated compounds along with the desired monoallylated product (75% yield). The best result was achieved when both the deprotonation with sodium hydride (1.15 equivalents) and the subsequent allylation (1.2 equivalents of allyl bromide) were conducted under... 

An exception is reported when the reactions are conducted using a twofold excess of dichloroethylsilane with equal equivalents of either aluminum chloride or aluminum bromide and /Moluenesull onic acid at 40° for two hours in dichloromethane. Under these conditions, 1-methylcyclohexene affords methylcyclohexane in 65-75% yield, whereas cyclohexene gives cyclohexane in 17-23% yield.192... 

This last electrochemical process is carried out in an undivided electrolysis cell fitted with a sacrificial magnesium anode and a nickel foam as cathode. The reaction is conducted in dimethylformamide in the presence of both NiBr2(bpy) as the catalyst and dried ZnBr2 (1.1 molar equivalents with respect to bromothiophene), which is used both as supporting electrolyte and as a zinc(II) ion source. The other conditions are the same as those described in the section concerning the aromatic halides. The yield of 3-thienylzinc bromide was roughly 80%, as determined by GC analysis after treatment with iodide (equation 34). 

Salinity was first rigorously defined by Knudsen (1902, p. 28) as the weight in grams of the dissolved inorganic matter in one kilogram of seawater after all bromide and iodide have been replaced by the equivalent amount of chloride and all carbonate converted to oxide. In 1978, the JPOTS decided that a new definition was needed for salinity that was based more on a salinity/conductivity ratio and was termed the practical salinity scale. 

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