* A|o, as H+

+ HSO-

(a) From the table, select half-cell reactions that, when combined, produce the overall reaction that characterizes battery operation.

(b) What is the emf generated by a pair of plates?

(c) As the battery operates, sulfuric acid is consumed. What is the voltage when the acid concentration has decreased to 3 M?

(d) How are the electrodes configured to produce 12 Volts output?

10.6 What is the EMF at 1273 K of the solid-state cell (Fe,Ni)1\FeO\\electrolyte\\(Fe,Ni)2\NiO in which (Fe,Ni)1 is an equimolar alloy of Fe and Ni and (Fe,Ni)2 is an alloy containing 30 mole percent Ni in Fe? The activity coefficient of the nickel component is given by:

10.7 What is the EMF produced by the cell Ni\NiO\\ electrolyte\\ TiO\ TiO, at 800oC? Note that the electrode on the right is a two-phase mixture of two oxides of titanium, both of which appear on the Ellingham diagram (Fig. 9.3).

10.8 An aqueous electrochemical cell consists of half cells denoted by A and B. The Nernst potential of half cell A is more positive than that of half cell B.

(a) If the cell were short-circuited, which electrode would be the cathode and which the anode?

(b) If electrode A consists of metal A and ion A+ and electrode B consists of metal B and ion B2+, write the half-cell reactions and the overall cell reaction,

(c) If the standard electrochemical potentials are sA and sB, what is the relationship between the concentrations of A+ and B2+ in the two compartments of the cell when the cell EMF is s and no current flows?

10.9 Consider the cell Cr\Cr2O\\ electrolyte\\H:O\H2 at 1000oC. If the H2O/H2 ratio in the gaseous electrode is 0.01, what is the cell EMF?

10.10 The cell O2(air)\\ electrolyte\\Pb IPbO(SiO2) operates at 700oC. The anode consists of metallic lead in contact with lead oxide which is dissolved in inert silica. The activity of PbO in the liquid oxide is 0.1. What is the EMF of this cell?

10.11 The overall reaction A+ + 2B4+ = A3+ + 2B3+ achieves equilibrium following addition of 1 mole of AX and 2 moles of B2Y3 to 1 liter of water. These compounds dissociate completely but only the cations react.

(a) write the mass-action law and the element and charge conservation equations.

(b) Combine the equations in part (a) into a single equation in the concentration of A+.

(c) Write the half-cell reactions (A) and (B) that combine to give the overall reaction..

The standard electrode potentials relevant to the overall reaction are given in the table:

Was this article helpful?

0 0
Getting Started With Solar

Getting Started With Solar

Do we really want the one thing that gives us its resources unconditionally to suffer even more than it is suffering now? Nature, is a part of our being from the earliest human days. We respect Nature and it gives us its bounty, but in the recent past greedy money hungry corporations have made us all so destructive, so wasteful.

Get My Free Ebook

Post a comment