. Practical physical chemistry . oncerned; for in the case of conductingsolutions, with which alone we are going to deal, the con-ductance does not depend on the whole of the material betweenthe electrodes, but only on the solute. When, therefore, wewish to compare different substances with respect to theconductivity which they exhibit in solution, we should comparechemically comparable quantities, equivalent or equi-molecular quantities. In this way we obtain the equivalentconductivity and the molecular conductivity. By equivalentconductivity is meant the conductance of a solution whichc
. Practical physical chemistry . oncerned; for in the case of conductingsolutions, with which alone we are going to deal, the con-ductance does not depend on the whole of the material betweenthe electrodes, but only on the solute. When, therefore, wewish to compare different substances with respect to theconductivity which they exhibit in solution, we should comparechemically comparable quantities, equivalent or equi-molecular quantities. In this way we obtain the equivalentconductivity and the molecular conductivity. By equivalentconductivity is meant the conductance of a solution whichcontains i of the solute, when placed betweentwo electrodes of indefinite size and i cm. apart. It is repre-sented by A, and is numerically equal to the specific con-ductance or conductivity (k) multiplied by the volume in cubiccentimetres (^) containing i of solute. Thatis, A = K. ^. By molecular conductivity is meant the conductance of asolution containing i mole of the solute when placed between. CONDUCTIVITY OF ELECTROLYTES 167 two electrodes of indefinite size and i cm. apart. It is repre-sented by yn = K . , where <^ is the volume in cubic centimetrescontaining i mole of the solute. Outline of Method and Apparatus.—For the purposeof measuring the resistance of a solution, one usually employsthe Wheatstone bridgemethod, the arrangementof which is shown dia-grammatically in Fig. , during the electro-lysis of an aqueous solu-tion between platinumelectrodes, gases areevolved, and a back elec-tromotive force (polarization ) therefore produced, onecannot readily measure the resistance of a liquid conductorby means of a direct current, but must employ an alternatingcurrent such as is given by an induction coil. The wiresfrom the secondary circuit of the induction coil, which shouldbe placed at a distance of two or three feet, so that itdoes not directly affect the telephone, are connected with theends of the wire ab, which is mad
Size: 2125px × 1176px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublisherlondonnewyorklongm
