Chapter Questions
For each of these pairs of half-reactions, write the balanced equationfor the overall cell reaction, and calculate the standard cell potential.Describe the reaction using cell notation. Refer to Chapter 19 to reviewwriting and balancing redox equations.$$\mathrm{Pt}^{2+}(\mathrm{aq})+2 \mathrm{e}^{-} \rightarrow \mathrm{Pt}(\mathrm{s}) \text { and } \mathrm{Sn}^{2+}(\mathrm{aq})+2 \mathrm{e}^{-} \rightarrow \mathrm{Sn}(\mathrm{s})$$
For each of these pairs of half-reactions, write the balanced equationfor the overall cell reaction, and calculate the standard cell potential.Describe the reaction using cell notation. Refer to Chapter 19 to reviewwriting and balancing redox equations.$$\mathrm{Co}^{2+}(\mathrm{aq})+2 \mathrm{e}^{-} \rightarrow \mathrm{Co}(\mathrm{s}) \text { and } \mathrm{Cr}^{3+}(\mathrm{aq})+3 \mathrm{e}^{-} \rightarrow \mathrm{Cr}(\mathrm{s})$$
For each of these pairs of half-reactions, write the balanced equationfor the overall cell reaction, and calculate the standard cell potential.Describe the reaction using cell notation. Refer to Chapter 19 to reviewwriting and balancing redox equations.$$\mathrm{Hg}^{2+}(\mathrm{aq})+2 \mathrm{e}^{-} \rightarrow \mathrm{Hg}(\mathrm{l}) \text { and } \mathrm{Cr}^{2+}(\mathrm{aq})+2 \mathrm{e}^{-} \rightarrow \mathrm{Cr}(\mathrm{s})$$
Challenge Write the balanced equation for the cell reaction andcalculate the standard cell potential for the reaction that occurs whenthese half-cells are connected. Describe the reaction using cell notation.$$\begin{array}{l}{\mathrm{NO}_{3}^{-}+4 \mathrm{H}^{+}+3 \mathrm{e}^{-} \rightarrow \mathrm{NO}+2 \mathrm{H}_{2} \mathrm{O}} \\ {\mathrm{O}_{2}+2 \mathrm{H}_{2} \mathrm{O}+4 \mathrm{e}^{-} \rightarrow 4 \mathrm{OH}^{-}}\end{array}$$
Calculate the cell potential to determine if each of the followingbalanced redox reactions is spontaneous as written. Use rable 20.1to help you determine the correct half-reactions.$$\mathrm{Sn}(\mathrm{s})+\mathrm{Cu}^{2+}(\mathrm{aq}) \rightarrow \mathrm{Sn}^{2+}(\mathrm{aq})+\mathrm{Cu}(\mathrm{s})$$
Calculate the cell potential to determine if each of the followingbalanced redox reactions is spontaneous as written. Use rable 20.1to help you determine the correct half-reactions.$$\mathrm{Mg}(\mathrm{s})+\mathrm{Pb}^{2+}(\mathrm{aq}) \rightarrow \mathrm{Pb}(\mathrm{s})+\mathrm{Mg}^{2+}(\mathrm{aq})$$
Calculate the cell potential to determine if each of the followingbalanced redox reactions is spontaneous as written. Use rable 20.1to help you determine the correct half-reactions.$$\begin{array}{l}{2 \mathrm{Mn}^{2+}(\mathrm{aq})+8 \mathrm{H}_{2} \mathrm{O}(1)+10 \mathrm{Hg}^{2+}(\mathrm{aq}) \rightarrow} \\ {2 \mathrm{MnO}_{4}-(\mathrm{aq})+16 \mathrm{H}^{+}(\mathrm{aq})+5 \mathrm{Hg}_{2}^{2+}(\mathrm{aq})}\end{array}$$
Calculate the cell potential to determine if each of the followingbalanced redox reactions is spontaneous as written. Use rable 20.1to help you determine the correct half-reactions.$$2 \mathrm{SO}_{4}^{2-}(\mathrm{aq})+\mathrm{Co}^{2+}(\mathrm{aq}) \rightarrow \mathrm{Co}(\mathrm{s})+\mathrm{S}_{2} \mathrm{O}_{8}^{2-}(\mathrm{aq})$$
Challenge Using table 20.1 , write the equation and determine thecell voltage $\left(E^{0}\right)$ for the following cell. Is the reaction spontaneous?$$AI\left|\mathrm{Al}^{3+} \| \mathrm{Hg}^{2+}\right| \mathrm{Hg}_{2}^{2+}$$
Describe the conditions under which a redox reaction causes anelectric current to flow through a wire.
Identify the components of a voltaic cell. Explain the role of each componentin the operation of the cell.
Write the balanced equation for the spontaneous cell reaction that occurs in acell with these reduction half-reactions.a. $A g^{+}(a q)+e^{-} \rightarrow A g(s)$ and $N i^{2+}(a q)+2 e^{-} \rightarrow$ Ni(s)b. $\mathrm{Mg}^{2+}(\mathrm{aq})+2 \mathrm{e}^{-} \rightarrow \mathrm{Mg}(\mathrm{s})$ and $2 \mathrm{H}^{+}(\mathrm{aq})+2 \mathrm{e}^{-} \rightarrow \mathrm{H}_{2}(\mathrm{g})$c. $\mathrm{Sn}^{2+}(\mathrm{aq})+2 \mathrm{e}^{-} \rightarrow \mathrm{Sn}(\mathrm{s})$ and $\mathrm{Fe}^{3+}(\mathrm{aq})+3 \mathrm{e}^{-} \rightarrow \mathrm{Fe}(\mathrm{s})$d. Pbl $_{2}(s)+2 e^{-} \rightarrow P b(s)+21-(a q)$ and $P t^{2+}(a q)+2 e^{-} \rightarrow P t(s)$
Determine the standard potential for electrochemical cells in which eachequation represents the overall cell reaction. Identify the reactions asspontaneous or nonspontaneous as written.$$\text { a. } 2 \mathrm{Al}^{3+}(\mathrm{aq})+3 \mathrm{Cu}(\mathrm{s}) \rightarrow 3 \mathrm{Cu}^{2+}(\mathrm{aq})+2 \mathrm{Al}(\mathrm{s})$$$$\text { b. }\mathrm{Hg}^{2+}(\mathrm{aq})+2 \mathrm{Cu}^{+}(\mathrm{aq}) \rightarrow 2 \mathrm{Cu}^{2+}(\mathrm{aq})+\mathrm{Hg}(\mathrm{l})$$$$\text { c. }C d(s)+2 N O_{3}-(a q)+4 H^{+}(a q) \rightarrow C d^{2+}(a q)+2 N O_{2}(g)+2 H_{2} O(l)$$
Design a concept map for Section $20.1,$ starting with the termelectrochemical cell. Incorporate all the new vocabulary terms in your map.
Identify what is reduced and what is oxidized in the zinc-carbondry-cell battery. What features make the alkaline dry cell an improvement overthe earlier type of dry-cell battery?
Explain what happens when a battery is recharged.
Describe the half-reactions that occur in a hydrogen fuel cell, and write theequation for the overall reaction.
Describe the function of a sacrificial anode. How is the function of a sacrificialanode similar to galvanization?
Explain why lithium is a good choice for the anode of a battery.
Calculate Use data from Table 20.1 to calculate the cell potential of thehydrogen-oxygen fuel cell described on page $723 .$
Design an Experiment Use your knowledge of acids from Chapter 18 todevise a method for determining whether a lead-acid battery can deliver fullcharge or is beginning to run down.
Define electrolysis and relate the definition to the spontaneity of redox reactions.
Explain why the products of the electrolysis of brine and the electrolysis ofmolten sodium chloride are different.
Describe how impure copper obtained from the smelting of ore is purified byelectrolysis.
Explain, by referring to the Hall-Heroult process, why recycling aluminum isvery important.
Describe the anode and cathode of an electrolytic cell in which gold is to beplated on an object.
Explain why producing a kilogram of silver from its ions by electrolysis requiresmuch less electric energy than producing a kilogram of aluminum from its ions.
Calculate Use Table 20.1 to calculate the voltage of the Down's cell. Shouldthe potential be positive or negative?
Summarize Write a short paragraph summarizing each of the three objectivesfor Section 20.3 in your own words.
What feature of an oxidation-reduction reaction allowsit to be used to generate an electric current?
Describe the process that releases electrons in a zinc-copper voltaic cell.
What is the function of a salt bridge in a voltaic cell?
What information do you need in order to determinethe standard voltage of a voltaic cell?
In a voltaic cell represented by All $A l^{3+} \| \mathrm{Cu}^{2+} | \mathrm{Cu},$ whatis oxidized and what is reduced as the cell delivers current?
Under what conditions are standard reduction potentialsmeasured?
In Figure 20.24 , identify the metal that is beingoxidized. Identify the cathode.
A salt bridge is filled with KNO $_{3}$ . Explain why it is necessary that the potassium ions move through the salt bridge to the cathode.
Recall that a reducing agent is the substance beingoxidized and an oxidizing agent is the substance beingreduced. Use Table 20.1 to select an oxidizing agentthat will convert Au to $\mathrm{Au}^{3+}$ but will not convert $\mathrm{Co}^{2+}$to $\mathrm{Co}^{3+} .$
Using Table 20.1 , write the standard cell notation foreach cell in which each of the following half-cells isconnected to the standard hydrogen electrode.$$\begin{array}{ll}{\text { a. } Z n | Z n^{2+}} & {\text { c. Cu } | C u^{2+}} \\ {\text { b. } \operatorname{Hg} | \mathrm{Hg}^{2+}} & {\text { d. Al } | A l^{3+}}\end{array}$$
Write the balanced chemical equation for the standardcell notations listed below.$$\begin{array}{l}{\text { a. } \mathrm{I}^{-}\left|\mathrm{I}_{2} \| \mathrm{Fe}^{3+}\right| \mathrm{Fe}^{2+}} \\ {\text { b. } \mathrm{Sn}\left|\mathrm{Sn}^{2+} \| \mathrm{Ag}^{+}\right| \mathrm{Ag}} \\ {\text { c. } \mathrm{Zn}\left|\mathrm{Zn}^{2+} \| \mathrm{Cd}^{2+}\right| \mathrm{Cd}}\end{array}$$
Calculate the cell potential for the following voltaic cells.$$\begin{array}{l}{\text { a. } 2 \mathrm{Ag}^{+}(\mathrm{aq})+\mathrm{Pb}(\mathrm{s}) \rightarrow \mathrm{Pb}^{2+}(\mathrm{aq})+2 \mathrm{Ag}(\mathrm{s})} \\ {\text { b. } \mathrm{Mn}(\mathrm{s})+\mathrm{Ni}^{2+}(\mathrm{aq}) \rightarrow \mathrm{Mn}^{2+}(\mathrm{aq})+\mathrm{Ni}} \\ {\text { c. } \mathrm{I}_{2}(\mathrm{aq})+\mathrm{Sn}(\mathrm{s}) \rightarrow 2 \mathrm{I}-(\mathrm{aq})+\mathrm{Sn}^{2+}(\mathrm{aq})}\end{array}$$
Figure 20.25 illustrates a voltaic cell consisting of a stripof zinc in a 1.0$M$ solution of zinc nitrate and a strip ofsilver in a 1.0$M$ solution of silver nitrate. Use the diagram and table 20.1 to answer these questions.$$\begin{array}{l}{\text { a. Identify the anode. }} \\ {\text { b. Identify the cathode. }} \\ {\text { c. Where does oxidation occur? }} \\ {\text { d. Where does reduction occur? }} \\ {\text { e. In which direction is the current flowing through }} \\ {\text { connecting wire? }} \\ {\text { fh. which direction are positive ions flowing through }} \\ {\text { g. What is the cell potential at 25 }^{\circ} \mathrm{C} \text { and } 1 \text { atm? }}\end{array}$$
What part of a zinc-carbon dry cell is the anode?Describe the reaction that takes place there.
How do primary and secondary batteries differ?
Lead-Acid Battery What substance is reduced in alead-acid storage battery? What substance is oxidized?What substances are produced in each reaction?
Biofuel Cell At the cathode of a biofuel cell, $\mathrm{Fe}^{3+}$ inpotassium hexacyanoiron (III) $\left(\mathrm{K}_{3}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]\right)$ is reduced to $\mathrm{Fe}^{2+}$ in potassium hexacyanoiron (II) $\left(\mathrm{K}_{4}\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]\right) .$ At the anode, reduced nicotinamide-adenine-dinucleotide (NADH) is oxidized to NAD $^{+} .$ Use the following standard reduction potential to determine the potentialof the cell.$$\begin{array}{ll}{\mathrm{NAD}^{+}+\mathrm{H}^{+}+2 \mathrm{e}^{-} \rightarrow \mathrm{NADH}} & {E^{0}=-0.320 \mathrm{V}} \\ {\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{3-}+1 \mathrm{e}^{-} \rightarrow\left[\mathrm{Fe}(\mathrm{CN})_{6}\right]^{4-}} & {E^{0}=+0.36 \mathrm{V}}\end{array}$$
Fuel Cells List two ways in which a fuel cell differsfrom an ordinary battery.
Galvanization What is galvanization? How doesgalvanizing iron protect it from corrosion?
Batteries Explain why a lead storage battery does notproduce a current when the level of $\mathrm{H}_{2} \mathrm{SO}_{4}$ is low.
Steel Wool is a bundle of filaments made of steel, analloy of iron and carbon. Which would be the best wayto store steel wool?$$\begin{array}{l}{\text { a. Store it in water. }} \\ {\text { b. Store it in open air. }} \\ {\text { c. Store it with a desiccant. }}\end{array}$$
Corrosion Protection List three ways metals can beprotected from corrosion.
Half-reactions for a lead-acid storage battery are below.$$\begin{array}{c}{\mathrm{PbO}_{2}(\mathrm{s})+\mathrm{SO}_{4}^{2-}(\mathrm{aq})+4 \mathrm{H}_{3} \mathrm{O}^{+}(\mathrm{aq})+2 \mathrm{e}^{-} \rightarrow} \\ {\mathrm{PbSO}_{4}(\mathrm{s})+6 \mathrm{H}_{2} \mathrm{O}(\mathrm{l}) \quad E^{0}=+1.685 \mathrm{V}} \\ {\mathrm{PbSO}_{4}(\mathrm{s})+2 \mathrm{e}^{-} \rightarrow \mathrm{Pb}(\mathrm{s})+\mathrm{SO}_{4}^{2-}(\mathrm{aq}) \quad E^{0}=-0.356 \mathrm{V}}\end{array}$$What is the standard cell potential for one cell in a carbattery?
The setup in Figure 20.26 acts as a battery.$$\begin{array}{l}{\text { a. Determine the reaction that takes place at the }} \\ {\text { copper strip. }} \\ {\text { b. Determine the reaction that takes place at the }} \\ {\text { magnesium wire. }} \\ {\text { c. Identify the anode. }} \\ {\text { d. Identify the anode. }} \\ {\text { e. Calculate the standard cell potential for this battery. }}\end{array}$$
You design a battery that uses a half-cell containingSn and $\mathrm{Sn}^{2+}$ and another half-cell containing Cu and$\mathrm{Cu}^{2+} .$ The copper electrode is the cathode, and the tinelectrode is the anode. Draw the battery and write thehalf-reactions that occur in each half-cell. What is themaximum voltage this battery can produce?
How can the spontaneous redox reaction of a voltaic cellbe reversed?
Where does oxidation take place in an electrolytic cell?
Down's Cell What reaction takes place at the cathodewhen molten sodium chloride is electrolyzed?
Industry Explain why the electrolysis of brine is doneon a large scale at many sites around the world.
Recycling Explain how recycling aluminum conservesenergy.
Describe what happens at the anode and the cathode inthe electrolysis of $\mathrm{KI}(\mathrm{aq}) .$
Electroplating Figure 20.27 shows a key being electroplated with copper in an electrolytic cell. Where does oxidation occur? Explain your answer.
Answer the following questions based on Figure 20.28$$\begin{array}{l}{\text { a. Which electrode grows? Write the reaction that }} \\ {\text { occurs at this electrode. }} \\ {\text { b. Which electrode disappears? Write the reaction that }} \\ {\text { occurs at this electrode. }}\end{array}$$
Using Figure 20.28 , explain what happens to the copperions in solution.
Why do electrons flow from one electrode to the otherin a voltaic cell?
Aluminum Production What substance is electrolyzedin the industrial process to produce aluminum metal?
Write the oxidation and reduction half-reactions for asilver-chromium voltaic cell. Identify the anode, cathode, and the direction of electron flow.
Determine whether each redox reaction is spontaneousor nonspontaneous.$$\begin{array}{l}{\text { a. } \mathrm{Mn}^{2+}(\mathrm{aq})+2 \mathrm{Br}^{-}(\mathrm{aq}) \rightarrow \mathrm{Br}_{2}(1)+\mathrm{Mn}(\mathrm{s})} \\ {\text { b. } 2 \mathrm{Fe}^{2+}(\mathrm{aq})+\mathrm{Sn}^{2+}(\mathrm{aq}) \rightarrow 2 \mathrm{Fe}^{3+}(\mathrm{aq})+\mathrm{Sn}(\mathrm{s})} \\ {\text { c. } \mathrm{Ni}^{2+}(\mathrm{aq})+\mathrm{Mg}(\mathrm{s}) \rightarrow \mathrm{Mg}^{2+}(\mathrm{aq})+\mathrm{Ni}(\mathrm{s})} \\ {\text { d. } \mathrm{Pb}^{2+}(\mathrm{aq})+2 \mathrm{Cu}^{+}(\mathrm{aq}) \rightarrow \mathrm{Pb}(\mathrm{s})+2 \mathrm{Cu}^{2+}(\mathrm{aq})}\end{array}$$
Determine the voltage of the cell in which each half-cellis connected to a Ag $|$ Ag $^{+}$ half-cell.$$\begin{array}{ll}{\text { a. } \mathrm{Be}^{2+} | \mathrm{Be}} & {\text { c. } \mathrm{Au}^{+} | \mathrm{Au}} \\ {\text { b. } \mathrm{S} | \mathrm{S}^{2-}} & {\text { d. } \mathrm{I}_{2} | \mathrm{I}^{-}}\end{array}$$
Corrosion Explain why water is necessary for the corrosion of iron.
Space Travel The space shuttle uses a $\mathrm{H}_{2} / \mathrm{O}_{2}$ fuel cell toproduce electricity.a. What is the reaction at the anode? At the cathode?b. What is the standard cell potential for the fuel cell?
Fuel Cells Explain how the oxidation of hydrogen in afuel cell differs from the oxidation of hydrogen when itburns in air.
Copper Refining In the electrolytic refining of copper,what factor determines which piece of copper is theanode and which is the cathode?
Storage Batteries Lead-acid batteries and otherrechargeable batteries are sometimes called storagebatteries. What is being stored in these batteries?
Corrosion Prevention Figure 20.29 shows how buriedsteel pipes can be protected against corrosion. The steelpipe is connected to a more active metal that corrodesinstead of the steel.a. What is the cathode? What is the anode?b. Describe how the magnesium metal protects the steel.
Predict Suppose that scientists had chosen the$\mathrm{Cu}^{2+} |$ Cu half-cell as a standard instead of the $\mathrm{H}^{+} | \mathrm{H}_{2}$half-cell? What would the potential of the hydrogen electrode be if the copper electrode were the standard?How would the relationships among the standard reduction potentials change?
Apply Suppose that you have a voltaic cell in which onehalf-cell is made up of a strip of tin immersed in a solution of tin $($ II) ions.$$\begin{array}{l}{\text { a. How could you tell by measuring voltage whether }} \\ {\text { the tin strip was acting as a cathode or an anode in }} \\ {\text { the cell? }} \\ {\text { b. How could you tell by simple observation whether }} \\ {\text { the tin strip was acting as a cathode or an anode? }}\end{array}$$
Hypothesize The potential of a half-cell varies withconcentration of reactants and products. For this reason,standard potentials are measured at 1$M$ concentration.Maintaining a pressure of 1 atm is especially importantin half-cells that involve gases as reactants or products.Suggest a reason why gas pressure is critical in these cells.
Analyze An earthen vessel was discovered in 1938 nearBaghdad. This ancient vessel contained an iron bar surrounded by a copper cylinder, as shown in Figure 20.30 . When filled with an electrolyte such as vinegar, this vessel might have acted as a battery.$$\begin{array}{l}{\text { a. Identify the cathode. }} \\ {\text { b. Identify the anode. }} \\ {\text { c. Calculate the standard cell potential of this battery. }}\end{array}$$
Apply During electrolysis, an electrolytic cell releasesbromine vapor and hydrogen gas. After electrolysis, thecell is found to contain a concentrated solution of potassium hydroxide. What was the composition of the cellbefore electrolysis began?
Hypothesize Suppose in galvanization, copper wasplated on iron instead of zinc. Would copper continue toprotect the iron from corrosion, as zinc does, if the copper coating became broken or cracked? Explain.
A battery is assembled using tin and mercury, whichhave the following reduction half-reactions:$$\begin{array}{l}{\mathrm{Sn}^{2+}+2 \mathrm{e}^{-} \rightarrow \mathrm{Sn}} \\ {\mathrm{Hg}^{2+}+2 \mathrm{e}^{-} \rightarrow \mathrm{Hg}}\end{array}$$$$\begin{array}{l}{\text { a. Write a balanced equation for the cell's reaction. }} \\ {\text { b. What is oxidized and what is reduced? Identify the }} \\ {\text { oxidizing agent and the reducing agent. }}\\{\text { c. Which reaction occurs at the anode? At the cathode? }} \\ {\text { d. What is the cell potential? Use Table } 20.1 .} \\ {\text { e. If sodium sulfate solution is in the salt bridge, in }} \\ {\text { which direction do the sulfate ions move? }}\end{array}$$
If the volume of a sample of chlorine gas is 8.2 $\mathrm{L}$ at1.2 atm and 306 $\mathrm{K}$ , what volume will the gas occupyat STP? (Chapter 13$)$
What is meant by solvation? Explain how this process is important for the dissolving of ionic salts in water. (Chapter 14)
Explain how the molarity of a solution is different fromits molality. (Chapter 14)
Define the calorie. State how the calorie is related to theCalorie and the joule. (Chapter 15$)$
Explain why you would find an aluminum chair to behotter to sit on than a wooden bench after each hadbeen in the sunlight for the same amount of time.(Chapter 15$)$
What does a negative sign for the free energy of areaction tell you about the reaction?$$\left(\Delta G_{\mathrm{system}}=\Delta H_{\mathrm{system}}-T \Delta S_{\mathrm{system}}\right)(\text {Chapter } 15)$$
According to the collision model of chemical reactions,how is it possible that two molecules can collide butnot react? (Chapter 16$)$
List five factors that can affect the rate of a reaction.(Chapter 16$)$
The decomposition reaction $\mathrm{A}_{2} \mathrm{B} \rightarrow 2 \mathrm{A}+\mathrm{B}$ proceeds toequilibrium at $499^{\circ} \mathrm{C}$ . Analysis of the equilibrium mix-ture shows $\left[\mathrm{A}_{2} \mathrm{B}\right]=0.855 \mathrm{mol} / \mathrm{L},[\mathrm{A}]=2.045 \mathrm{mol} / \mathrm{L}$and $[\mathrm{B}]=1.026 \mathrm{mol} / \mathrm{L} .$ What is $K \mathrm{eq} ?($Chapter 17$)$
What is the solubility in mol/L of silver iodide, AgI. $K_{\mathrm{sp}}$for AgI is $3.5 \times 10^{-17} .($Chapter 17$)$
If you have a solution of a strong acid, is that the same ashaving a concentrated solution of the acid? Explain youranswer. (Chapter 18$)$
What are the oxidation numbers for the elements in theion $\mathrm{PO}_{4}^{3-} ?$ (Chapter 19$)$
Sunken Ships Study of the sunken ocean linerTitanic has opened the possibility that deteriorationof the steel hull might be partly due to the presence ofrusticle communities. Research how the biologicalactivity of rusticle communities results in the oxidation of iron. Write an essay that describes the role ofrusticle communities in the destruction of the Titanic.
Statue of Liberty Several years ago, the supportingstructure of the Statue of Liberty became so corrodedthat it had to be replaced entirely. Find out what thestructure was made of and why it corroded so badly.Write a report that explains the chemical processesinvolved and include a time line of the statue, startingin France before 1886 .
Electrochemical Biological Reactions Standard reductionpotentials for some important biological reactions are givenin Table $20.2 .$ The strongest oxidizing agent generally available in biological systems is molecular oxygen. Consider the oxidation of reduced nicotinamide-adenine-dinucleotide$(N A D H)$ by molecular oxygen. The reaction is the following.$$2 \mathrm{NADH}+2 \mathrm{H}^{+}+\mathrm{O}_{2} \rightarrow 2 \mathrm{NAD}^{+}+2 \mathrm{H}_{2} \mathrm{O}$$Write the two half-reactions that take place inthis reaction.
Electrochemical Biological Reactions Standard reductionpotentials for some important biological reactions are givenin Table $20.2 .$ The strongest oxidizing agent generally available in biological systems is molecular oxygen. Consider the oxidation of reduced nicotinamide-adenine-dinucleotide$(N A D H)$ by molecular oxygen. The reaction is the following.$$2 \mathrm{NADH}+2 \mathrm{H}^{+}+\mathrm{O}_{2} \rightarrow 2 \mathrm{NAD}^{+}+2 \mathrm{H}_{2} \mathrm{O}$$Calculate the cell potential of this reaction usingtable 20.1 on page 712 and Table 20.2 .
Electrochemical Biological Reactions Standard reductionpotentials for some important biological reactions are givenin Table $20.2 .$ The strongest oxidizing agent generally available in biological systems is molecular oxygen. Consider the oxidation of reduced nicotinamide-adenine-dinucleotide$(N A D H)$ by molecular oxygen. The reaction is the following.$$2 \mathrm{NADH}+2 \mathrm{H}^{+}+\mathrm{O}_{2} \rightarrow 2 \mathrm{NAD}^{+}+2 \mathrm{H}_{2} \mathrm{O}$$Will NAD $^{+}$ oxidize $\mathrm{Fe}^{2+}$ to $\mathrm{Fe}^{3+} ?$ Explain youranswer.