Foreign salts

Foreign salts may frequently be present without interference and are, indeed, usually added as the supporting electrolyte in order to eliminate the migration current. 

While in this brief section reference has been made only to viscosity and osmotic-pressure properties of polyelectrolytes, the difference between them and uncharged polymers persists in all dilute solution measurements. The characteristic effect is that in the absence of foreign salts in the polyelectrolyte system the behavior in dilute solutions is governed by the very long-range molecular interaction forces. 

This solution obviously contains zinc salts. Solutions completely free of foreign salts are obtained either by dissolving chromium (III) acetate or, better, by dissolving electrolytic chromium in dilute HCl, as described, for example, in the procedure for fyis(2,2 -dipy-rldyl)chromium (II) perchlorate. 

In the absence of foreign salts, the concentration of Na" " can be calculated simply from the concentration of silica, Cg, and the ratio r since... 

No foreign salt added. BrSnsted and Livingston J. Am. Chem. Soc.,... 

The equilibrium dissociation constant X iss is difficult to obtain with a sufficient degree of accuracy from conductivity measurements, but it can be found from reaction kinetics measurements by adding a foreign salt with the same gegenion. With Kdiss = [P ] /[C ], equation (18-80) becomes... 

The dissociation of growing macroions is greatly reduced by the addition of foreign salts (for example, Kalignost in the polymerization of styrene in tetrahydrofuran started by sodium naphthalide) ... 

The slope of a plot of measured rates Up against the reciprocal of the total sodium gegenion concentration gives /C(-.)Xdiss- Since, according to equation (18-80), /C(-)Xdis s is obtained for measurements in the absence of foreign salts, the individual values of k( ) and X iss can be obtained from these data. 

The temperature and salt concentration were not maintained constant for the data listed in table II. The calculated values are not in excellent agreement the effect of temperature and foreign salts such as ammonium chloride and sodium chloride, which usually effects the stability of chelates, must be taken into consideration. 

Henry published analyses of British and foreign common salt which showed that the first was much purer than the foreign salt then preferred by the Irish provision curers. Londons, a Northwich firm, purified rock salt by fusion in a reverberatory furnace, a process patented in 1903 by Lee in Ireland. ... 

Salt Effects. The solution to the problem came largely from investigations of salt effects in kinetics. The addition of foreign salts, which do not have an ion in common with any ion directly involved in the reaction, is often found to have an important kinetic effect. At first the explanations were given in terms of positive or negative catalysis, but this idea proved to be unhelpful. It is best instead to regard salt effects as environmental effects and to explain them in terms of the activity coefficients of the reacting species. 

For the production of fine coloured and highly transparent soaps, it is absolutely necessary to use very pure raw materials in the case under discussion it is strongly recommended to use the lye obtained by means of lime, not that prepared from wood ashes but that froin potash, as lye obtained from wood ashes is generally of a fairly dark colour. Skill is needed in dissolving the potash generally one and a hall times its weight in water is poured over it, and for this purpose very cold water is used. In this the potassium carbonate only is principally dissolved, as the foreign salts remain undissolved. The solution is separated from the deposit, diluted sufficiently with water, and rendered caustic with linie. 

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