Electrical Conductivity of Aqueous Solutions

Arrhenius, insofar as his profession could be defined at all, began as a physicist. He worked with a physics professor in Stockholm and presented a thesis on the electrical conductivities of aqueous solutions of salts. A recent biography (Crawford 1996) presents in detail the humiliating treatment of Arrhenius by his sceptical examiners in 1884, which nearly put an end to his scientific career he was not adjudged fit for a university career. He was not the last innovator to have trouble with examiners. Yet, a bare 19 years later, in 1903, he received the Nobel Prize for Chemistry. It shows the unusual attitude of this founder of physical chemistry that he was distinctly surprised not to receive the Physics Prize, because he thought of himself as a physicist. 

The conductivity of sodium dodecyl sulfate in aqueous solution and in sodium chloride solutions was studied by Williams et al. [98] to determine the CMC. Goddard and Benson [146] studied the electrical conductivity of aqueous solutions of sodium octyl, decyl, and dodecyl sulfates over concentration ranges about the respective CMC and at temperatures from 10°C to 55°C. Figure 14 shows the results obtained by Goddard and Benson for the specific conductivity of sodium dodecyl sulfate and Table 25 shows the coefficients a and p of the linear equation of the specific conductivity, in mho/cm, vs. the molality of the solution at 25°C. Micellization parameters have been studied in detail from conductivity data in a recent work of Shanks and Franses [147]. 

Electrical Conductivity of Aqueous Solutions generally high low or zero... 

Electrical Conductance of Aqueous Solutions of Ammonia and Metal Hydroxides. Check the electrical conductance of 1 W solutions of sodium hydroxide, potassium hydroxide, and ammonia. Record the ammeter readings. Arrange the studied alkalies in a series according to their activity. Acquaint yourself with the degree of dissociation and the dissociation constants of acids and bases (see Appendix 1, Tables 9 and 10). Why is the term apparent degree of dissociation used to characterize the dissociation of strong electrolytes ... 

Molecular Weight and Constitution.—The electrical conductivity of aqueous solutions of potassium perdisulphate supplies distinct evidence of the dibasicity of the corresponding acid.12 This is confirmed by molecular weight determinations made by the cryoscopie method... 

Other physical phenomena that may be associated, at least partially, with complex formation are the effect of a salt on the viscosity of aqueous solutions of a sugar and the effect of carbohydrates on the electrical conductivity of aqueous solutions of electrolytes. Measurements have been made of the increase in viscosity of aqueous sucrose solutions caused by the presence of potassium acetate, potassium chloride, potassium oxalate, and the potassium and calcium salt of 5-oxo-2-pyrrolidinecarboxylic acid.81 Potassium acetate has a greater effect than potassium chloride, and calcium ion is more effective than potassium ion. Conductivities of 0.01-0.05 N aqueous solutions of potassium chloride, sodium chloride, potassium sulfate, sodium sulfate, sodium carbonate, potassium bicarbonate, potassium hydroxide, and sodium hydroxide, ammonium hydroxide, and calcium sulfate, in both the presence and absence of sucrose, have been determined by Selix.88 At a sucrose concentration of 15° Brix (15.9 g. of sucrose/100 ml. of solution), an increase of 1° Brix in sucrose causes a 4% decrease in conductivity. Landt and Bodea88 studied dilute aqueous solutions of potassium chloride, sodium chloride, barium chloride, and tetra-... 

Noyes, The Electrical Conductivities of Aqueous Solutions, Washington, 1907 Noyes, Meloher, Cooper and Eastman, Zeitsch. physikal. Chem., 1910, 70, 335. See also Kohlrauseh and Holborn, [Pg.162]

The electrical conductivities of aqueous solutions of pyrophosphoric acid are as follows —4... 

Fig. A.5. Electrical conductivity versus mass% H2SO4 in sulfuric acid. Source Roughton, J.E. (1951) The electrical conductivity of aqueous solutions of sulphuric acid from 25°C to 155°C, J. Appl. Chem.,1, Supplementary Issue, No. 2., 141 144.

A study of the electric conductivities of aqueous solutions of the salt indicates that the hydrolysis proceeds in two stages, embodying (1) a rapid change unaccompanied by precipitation, and (2) a slower change, progressing at a measurable rate, and accompanied by the production of a so-called basic salt.8 Colloidal ferric hydroxide does not appear to be formed during hydrolysis,9 the salt thus differing from ferric chloride and nitrate. 

The results obtained for the osmotic pressures and electric conductivities of aqueous solutions of calcium and strontium ferroeyanides (see pp. 208 and 220) indicate that these molecules possess the double formula, M4[Fe(CN)6]2. On the other hand, tetra-ethyl ferrocyanide is known to have the single formula, (C2H5)4Fe(CN)6.s... 

Electrical conductivity of aqueous solutions. The circuit will be completed and will allow current to flow only when there are charge carriers (ions) in the solution. Note Water molecules are present but not shown in these pictures, (a) A hydrochloric acid solution, which is a strong electrolyte, contains ions that re adily conduct the current and give a brightly lit bulb, (b) An acetic acid solution, which is a weak electrolyte, contains only a few ions and does not conduct as much current as a strong electrolyte. The bulb is only dimly lit. (c) A sucrose solution, which is a nonelectrolyte, contains no ions and does not conduct a current. The bulb remains unlit. 

Table XII.—Molecular Electrical Conductivities of Aqueous Solutions of...

Werner realized that he could test his hypothesis by measuring the electrical conductivity of aqueous solutions of the salts of these complex ions. Ions are the electrical conductors in aqueous solutions, and the conductivity is proportional to the ion concentration. If Werner s proposal was correct, then an aqueous solution of Compound 1, for example, should have a molar conductivity close to that of an aqueous solution of A1(N03)3, which also forms four ions per formula unit on complete dissociation in water (one 3+ ion and three 1— ions). His experiments confirmed that the conductivities of these two solutions were, indeed, similar. Furthermore the conductivity of aqueous solutions of compound 2 was close to those of Mg(N03)i, and solutions of compound 3 conducted electricity about as well as those containing NaN03. Compound 4, in contrast, did not dissociate into ions when dissolved in water, producing a solution of very low electrical conductivity. 

An important factor in the chemistry of water is its electric conductivity specific conductivity) x. The electric conductivity x is the conductivity of a cube of a conductor (solution) with an edge of 1 m. The unit is in the terms of S m. The electric conductivity of aqueous solutions is a function of the concentration of ions in a solution, the nature of dissolved substance and the temperature. 

The following table gives the electrical conductivity of aqueous solutions of some acids, bases, and salts as a function of concentration. AU values refer to 20 °C. The conductivity k (often called specific conductance in older literature) is the reciprocal of the resistivity. The molar conductivity A is related to this by A = k/c, where c is the amount-of-substance concentration of the electrolyte. Thus if K has units of millisiemens per centimeter (mS/cm), as in this table, and c is expressed in mol/L, then A has units of S cm mol b For these electrolytes the concentration c correspond-... 

Electrical conductivity of aqueous solutions. The result of this experiment is strong evidence that ionic compounds dissolved in water exist in the form of separated ions. 

Apelblat A, Bester-Rogac M, Barthel J, Neueder R (2006) An analysis of electrical conductances of aqueous solutions of polybasic organic acids. Benzenehexacarboxylic (mellitic) acid and its neutral and acidic salts. J Phys Chem B 110 8893-8906... 

Since ionic surfactants carry a charge with an accompanying counterion, these will contribute to the electrical conductivity of aqueous solutions. Thus, by measuring the electrical conductivity, the adsorption of ionic surfactants can then be determined. 

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