. Practical physical chemistry . this experiment the apparatus shown in Fig. 66 maybe employed. The tubes are firstfilled with a solution of silver nitrate (about — ), the composition by weight of which is determined by titration, orby electrolytic deposition. Into thetubes are fixed by means of corks, twosilver electrodes made by fixing piecesof thick silver rod to copper wires,and cementing the latter into glasstubes so that only the silver is ex-posed. The rod to be used as anodesjiould be freshly plated with silver. As we shall be concerned only withthe change in the composition of thesolu
. Practical physical chemistry . this experiment the apparatus shown in Fig. 66 maybe employed. The tubes are firstfilled with a solution of silver nitrate (about — ), the composition by weight of which is determined by titration, orby electrolytic deposition. Into thetubes are fixed by means of corks, twosilver electrodes made by fixing piecesof thick silver rod to copper wires,and cementing the latter into glasstubes so that only the silver is ex-posed. The rod to be used as anodesjiould be freshly plated with silver. As we shall be concerned only withthe change in the composition of thesolution at the anode, it is not neces-sary to have a silver cathode; and itsplace can be taken by a copper elec-trode. In this case a layer (about 5cm. in depth) of a strong solution, ofcopper nitrate, slightly acidified withnitric acid, is first introduced into theshorter limb of the apparatus, and therest of the apparatus then filled with the silver nitrate must be done carefully so as not to disturb the layer of. Fig. 66. 2o8 PRACTICAL PHYSICAL CHEMISTRY copper nitrate. It is most easily accomplished by placinga disc of cork on the top of the copper nitrate solution, andrunning the silver nitrate solution on to this from a pipette. The apparatus is now connected with a battery, and acurrent of about ooi or oo2 amp. sent through the solu-tion. A milliammeter and a copper voltameter, togetherwith a sliding resistance, should also be inserted in the circuit,all in series; the ammeter being used for the approximateregulation of the current, and the voltameter for the determi-nation of the total amount of electricity passed through thesolution. The electrical potential which must be employedin order to give a current of about lo milliamperes will depend,of course, on the resistance, and, therefore, on the dimensionsof the apparatus employed. In general, a potential of 30-40volts will be necessary; and where this cannot be obtainedfrom a battery, one may make use of t
Size: 948px × 2636px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublisherlondonnewyorklongm
