Electrical Conductance of Solutions

Pour 50 ml of a 0.1 aqueous or ethanol solution of potassium hydroxide or potassium nitrate into four 100-ml heakers (use two of them for each solvent). Using a stationary setnp for determining the electrical conductance (Fig. 50), check whether these solutions conduct an electric current. For this purpose, immerse the carhon electrodes into a heaker with the relevant solution and observe the reading of the ammeter. See that the electrodes are always immersed to the same depth. When transferring the electrodes from one solution into another one, wash them with distilled water. 

What explains the different electrical conductance of an aqueous and ethanol solutions of the same substance in the same concentration (jV) What is called the dielectric constant (permittivity)  

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When an ionic solution contains neutral molecules, their presence may be inferred from the osmotic and thermodynamic properties of the solution. In addition there are two important effects that disclose the presence of neutral molecules (1) in many cases the absorption spectrum for visible or ultraviolet light is different for a neutral molecule in solution and for the ions into which it dissociates (2) historically, it has been mainly the electrical conductivity of solutions that has been studied to elucidate the relation between weak and strong electrolytes. For each ionic solution the conductivity problem may be stated as follows in this solution is it true that at any moment every ion responds to the applied field as a free ion, or must we say that a certain fraction of the solute fails to respond to the field as free ions, either because it consists of neutral undissociated molecules, or for some other reason ... 

Sonication of 0.05 M Hg2(N03)2 solution for 10,20 and 30 min and the simultaneous measurements of conductivity, temperature change and turbidity (Table 9.2) indicated a rise in the turbidity due to the formation of an insoluble precipitate. This could probably be due to the formation of Hg2(OH)2, as a consequence of hydrolysis, along with Hg free radical and Hg° particles which could be responsible for increase in the turbidity after sonication. The turbidity increased further with time. Mobility of NO3 ions was more or less restricted due to resonance in this ion, which helped, in the smooth and uniform distribution of charge density over NO3 ion surface. Hence the contribution of NOJ ion towards the electrical conductance was perhaps much too less than the conduction of cationic species with which it was associated in the molecular (compound) form. Since in case of Hg2(N03)2, Hg2(OH)2 species were being formed which also destroyed the cationic nature of Hg22+, therefore a decrease in the electrical conductance of solution could be predicted. The simultaneous passivity of its anionic part did not increase the conductivity due to rise in temperature as anticipated and could be seen through the Table 9.2. These observations could now be summarized in reaction steps as under ... 

K = electrical conductivity of solution Vf = flow rate volume/time of solution through ES capillary y = surface tension of solvent e = permitivity of solvent Co = permitivity of vacuum e/ o = dielectric constant of solvent... 

Observing and Inferring The electrical conductivities of solutions of weak acids, such as acetic acid, are related to the degree of ionization of the acid. 

The electrical conductivity of solutions is measured for at least three distinct purposes ... 

Fig. 10.17 Electrical conductivity of solutions Na in NH3 at 240 K, due to Kraus (1921). A marks the minimum in conductance per ion pair shown in Fig. 10.15. From Cohen...

The equivalent electrical conductivities of solutions of the alkali chlorides59 containing a mol. of the salt in i litres of water, at 25°, are ... 

HYDROGEN BONDING AND THE ELECTRICAL CONDUCTIVITIES OF SOLUTIONS IN SULPHURIC ACID THE MOBILITIES OF THE IONS... 

Other indications of the existence of hydrates are found in the curve representing the electrical conductivity of solutions of various... 

Among other electrical properties of nitrocellulose, attention should be paid to the experimental work on the electrical conductivity of solutions. Thus Dobry [143] found the conductivity of a nitrocellulose solution in acetone to be proportional to its concentration. Experiments on the electrophoresis of solutions made by Lantz and Pickett [144] demonstrated that the particles of nitrocellulose carry a negative charge. Electrolysis of the solution causes the nitrocellulose gel to collect at the anode. This gel may contain the metal of which the anode is constructed, as demonstrated byApard [145]. 

Measurements of the electrical conductivity of solutions of alkali tantalates have been made,1 but no definite conclusions are deducible as to the complexity of the ions present. 

Fig. 43.—The Effect of Temperature on the Electrical Conductivity of Solutions of Phosphoric Acid.

Table V.—Electrical Conductivities of Solutions of Phosphoric Acid.

Millen and Watson [48] confirmed this observation by examining the infra-red spectra of the same solutions. Very recently Goulden, Lee and Millen [48a] examined the electrical conductances of solutions of dinitrogen tetroxide in nitric acid and came to the conclusion that N204 is subjected to nearly complete ionization according to eqn. (17). 

Salt content or electrical conductivity of solution [S(II) insoluble vs. S(VI)04 soluble]... 

Ammonium silicate.—No ammonium salt of silicic acid has been isolated.16 Experiments on the electrical conductivity of solutions of silicic acid in aqueous ammonia indicate the probability of the formation of a true ammonium silicate in solution.17... 

A study of the osmotic pressures and electric conductivities of solutions of strontium ferrocyanide in water leads to the conclusion 4 that the negative radicles are associated to double ions, namely [Fe(CN)6]a " ... 

The equivalent electrical conductivities of solutions of the alkali chlorides... 

Tin trimethyl hydroxide is isolated from the iodide by action of potassium hydroxide. It crystallises in prisms and is volatile iii steam. The aqueous solution is strongly alkaline, and the solubility in alcohol is greater than in water. With tin trimethyl halides it forms complexes of the type (Me jSnOH)2.Me jSnX, the bromide melting at 113° to 115° C. with decomposition iodide 143° to 153° C. with decomposition also the type Me SnOH.MejjSnX.HgO, the chloride M.pt. 90° C. bromide, M.pt. 210° to 211° C. with decomposition iodide, M.pt. 221° C. with decomposition. The electrical conductivity of solutions of the hydroxide has been determined by Bredig.-... 

Phosgene may be detected by the variations in the electrical resistance of a heated wire of palladium-silver alloy surrounded by the gas [1706], Methods based upon the electrical conductance of solutions, however, depend upon the production of ionic compounds for their measurement [1173,2093a], and are particularly susceptible to interference from hydrogen chloride. 

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