University College - Chemistry Chem 112A Lecture 29: Recharging secondary cells and reduction strength
4 Apr 2017
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Recharging battery apply external potential to reverse polarity. Would be dangerous to do this for primary cells. For the zinc-carbon dry cell, with the electrolyte ammonium chloride. + + 2e- -> 2nh3 (g) + h2 (g) Zn -> zn2+ + 2e: zn2+ + nh3 + cl- -> zn(nh3)2cl2. When polarity is reversed the pressure is increased while also in the presence of. Ragone plot power density vs energy density. Fuel cells have a better energy density than batteries, but provide less power. Continuous process as long as h2 and o2 are present. H2 is oxidized at anode: 2h2 + 4oh- O2 is reduced at cathode: 2h2o + o2 + 4e- -> 4oh- Ecell = 1. 23 v therefore a galvanic cell and g < 0. The higher the reduction potential the higher the oxidizing strength and the lower the reducing strength. The lower the reduction potential the higher the reducing strength and the lower the oxidizing strength.
