Problem 38
Write the cathode, anode, and net cell reaction in a hydrogen-oxygen fuel cell.
Problem 39
What advantages do fuel cells offer over conventional means of obtaining electrical power by the combustion of fuels?
Problem 40
What electrical charges do the anode and the cathode carry in an electrolytic cell? What does the term inert electrode mean?
Problem 41
Why must electrolysis reactions occur at the electrodes in order for electrolytic conduction to continue?
Problem 42
Why must \(\mathrm{NaCl}\) be melted before it is electrolyzed to give \(\mathrm{Na}\) and \(\mathrm{Cl}_{2}\) ? Write the anode, cathode, and overall cell reactions for the electrolysis of molten \(\mathrm{NaCl}\).
Problem 43
Write half-reactions for the oxidation and the reduction of water.
Problem 46
Using the same current, which will require the greater length of time: depositing \(0.10 \mathrm{~mol}\) Cu from a \(\mathrm{Cu}^{2+}\) solution, or depositing \(0.10 \mathrm{~mol}\) of \(\mathrm{Cr}\) from a \(\mathrm{Cr}^{3+}\) solution? Explain your reasoning.
Problem 50
Describe the Hall-Héroult process for producing metallic aluminum. What half- reaction occurs at the anode? What half-reaction occurs at the cathode? What is the overall cell reaction?
Problem 51
In the Hall-Héroult process, why must the carbon anodes be replaced frequently?
Problem 55
Write the half-reactions and the balanced cell reaction for the following galvanic cells. $$ \begin{array}{l} \text { (a) } \mathrm{Zn}(s)\left|\mathrm{Zn}^{2+}(a q) \| \mathrm{Cr}^{3+}(a q)\right| \mathrm{Cr}(s) \\ \text { (b) } \mathrm{Pb}(s), \mathrm{PbSO}_{4}(s) \mid \mathrm{HSO}_{4}^{-}(a q) \| \\ \mathrm{H}^{+}(a q), \mathrm{HSO}_{4}^{2-}(a q) \mid \mathrm{PbO}_{2}(s), \mathrm{PbSO}_{4}(s) \\ \text { (c) } \mathrm{Mg}(s)\left|\mathrm{Mg}^{2+}(a q) \| \mathrm{Sn}^{2+}(a q)\right| \mathrm{Sn}(s) \end{array} $$
