Page:Text-book of Electrochemistry.djvu/165

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��CONDUCTIVITY OF ELECTROLYTES. chap.

��of the ions increase, i,e. for most ions about 2'5 per cent, per degree.

The electrolytic friction of the ions is greater in other solvents than in water. The addition of a very small quantity of another non-conductor to the water appreciably increases the friction of the ions, and consequently decreases the conductivity of the solution, just as the internal friction of the liquid is altered by a similar addition. The action of foreign substances on the internal friction runs almost parallel with that on the electrolytic friction. Thus I have found (17) that the addition of one per cent, by volume of the non-conductors mentioned in the following table raises the internal friction, and the electrolytic friction of the commonly occurring ions at 25° by the amount given in the table. If greater quantities be added, there is a pro- portional increase in the electrolytic friction, but also a diminution of the degree of dissociation of the electrolyte, particularly if a concentrated solution of this is used. On this subject Walker (18) has made an interesting investi- gation on the action of alcohols on diethylammonium chloride. It appears that the degree of dissociation is most affected by those substances which contain relatively least hydroxyl.

��Percentage increMe of the internal and ionlo firiction by addition of 1 per cent, by Tolame of the non- oondnctor.

��Internal friction of the water

H ion

OH ion

Monovalent salt ions. . . SO4, CO5, etc. (divalent

negative ions) .... Ba, Zn, etc. (divalent positive

ions)

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��As the addition increases, the function of the water as solvent gradually diminishes, and we obtain electrolytic

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