. Introduction to inorganic chemistry . hloride, andblue vitriol crystals are thrownin and dissolve. So long asthe contents are not disturbed,the solutions require no porousseptum to keep them apart. Itis true that, when the currentis not jbeing used, and the cellis not working, the cupric sul-phate diffuses upwards. Duringthe time that the circuit isclosed, however, the effects ofdiffusion are nullified by themigration of the cuprion awayfrom the zinc and towards thepositive pole. The actual elec-tromotive force of the current delivered by this cell is a little over1 volt, and accords, theref
. Introduction to inorganic chemistry . hloride, andblue vitriol crystals are thrownin and dissolve. So long asthe contents are not disturbed,the solutions require no porousseptum to keep them apart. Itis true that, when the currentis not jbeing used, and the cellis not working, the cupric sul-phate diffuses upwards. Duringthe time that the circuit isclosed, however, the effects ofdiffusion are nullified by themigration of the cuprion awayfrom the zinc and towards thepositive pole. The actual elec-tromotive force of the current delivered by this cell is a little over1 volt, and accords, therefore, with the value calculated from the poten-tial difference observed at each of the two poles. The cell Zn-H ( volts) works without a septum, provided thedirect action of the zinc on the acid is minimized by adequate amalga-mation with mercury. It gives a very inconstant electromotive force,however, because the platinum plate used as the cathode becomes cov-ered with bubbles of hydrogen, and so the internal resistance of the cell. Fig, 103. ELECTROMOTIVE CHEMISTRY 673 is greatly increased. Tlie polarization (p. 324) also diminlslies theelectromotive force. These difilculties are remedied, and, in fact, agreat increase in the of the cell is effected, by surrounding thecathode with an oxidizing agent which shall convert the hydrogen intowater. The energy obtainable is thus that of a strong oxidizing agenton zinc, and not merely that of an acid. In the Bunsen cell the cath-ode is a carbon block surrounded by concentrated nitric acid. In thebichromate battery it is a carbon block with chromic acid. Each ofthese cells gives an of volts. In the Leolanche cell the cath-ode is a mixture of carbon and manganese dioxide, and the fluid is a so-lution of ammonium chloride from which the zinc displaces dioxide, being solid, oxidizes the hydrogen slowly, and the cell canbe used for only a few minutes at a time without becoming is
Size: 1566px × 1596px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookidcu3192400298, bookyear1908
