
To write:
The balanced equation for the cell for each pair and identify which half-reaction takes place at anode and which at cathode.

Answer to Problem 17.32QA
Solution:
a) Anode:
Cathode:
----------------------------------------------------------------------------------
Balanced equation:
b) Anode:
Cathode:
----------------------------------------------------------------------------------------------------------------
Balanced equation:
c) Anode:
Cathode:
--------------------------------------------------------------------------------------------------
Balanced equation:
Explanation of Solution
1) Concept:
We are asked to write and balance the cell reaction from the given pair. Values of standard reduction potential are given in appendix 6, table A6.1. Higher the standard reduction potential, higher is the tendency to reduce. So the element that has a negative or small value of standard reduction potential is more likely to oxidize. Therefore, we reverse that reaction to make it an oxidation half reaction. For an
Adding two half
2) Formula:
3) Given:
i)
ii)
iii)
4) Calculations:
The standard reduction potential values for all these reactions are taken from the Appendix 6, table A6.1.
a.
Since the standard reduction potential for
In the first pair of reactions, the number of electrons is not the same, so we need to balance it. So, multiply the second reaction by 2, and we get
So,
Now add two half balanced reactions:
Anode:
Cathode:
-------------------------------------------------------------------------
b.
Since the standard reduction potential for the second reaction is higher than that of the first reaction, the second given reaction will serve as a cathode and undergo a reduction half reaction, and the first given reaction will serve as an anode and undergo an oxidation half reaction.
In the second pair of reactions, the number of electrons is not the same, so we need to balance it. So, multiply the first reaction by
Now add two half reactions:
Anode:
Cathode:
----------------------------------------------------------------------------------------------------------------
c.
Since the standard reduction potential for the second reaction is higher than that of the first reaction, the second given reaction will serve as a cathode and undergo a reduction half reaction, and the first given reaction will serve as an anode and undergo an oxidation half reaction.
In the third pair of reactions, electrons are not the same, so we need to balance them, so, multiply second reaction by 2. We get
So,
Now add two half balanced reactions:
Anode:
Cathode:
-------------------------------------------------------------------------------------------
Conclusion:
For an electrochemical cell, higher the standard reduction potential, higher is the tendency to reduce (cathode). So, the reaction that has a negative or small value of standard reduction potential is more likely to oxidize (anode). Therefore, this reaction is reversed to get the oxidation reaction that will take place at the anode. The reaction with a higher value of standard reduction potential is the reduction reaction that will take place at the cathode.
Want to see more full solutions like this?
Chapter 17 Solutions
Chemistry: An Atoms-Focused Approach
- I need help with the followingarrow_forwardFor Raman spectroscopy/imaging, which statement is not true regarding its disadvantages? a) Limited spatial resolution. b) Short integration time. c) A one-dimensional technique. d) Weak signal, only 1 in 108 incident photons is Raman scattered. e) Fluorescence interference.arrow_forwardUsing a cell of known pathlength b = 1.25115 x 10-3 cm, a water absorption spectrum was measured. The band at 1645 cm-1, assigned to the O-H bending, showed an absorbance, A, of 1.40. a) Assuming that water density is 1.00 g/mL, calculate the water molar concentration c (hint: M= mole/L) b) Calculate the molar absorptivity, a, of the 1645 cm-1 band c) The transmitted light, I, can be written as I= Ioexp(-xb), where x is the absorption coefficient (sometimes designated as alpha), Io is the input light, and b is the cell pathlength. Prove that x= (ln10)*x*c. (Please provide a full derivation of the equation for x from the equation for I). d) Calculate x for the 1645 cm-1 bandarrow_forward
- For CARS, which statement is not true regarding its advantages? a) Contrast signal based on vibrational characteristics, no need for fluorescent tagging. b) Stronger signals than spontaneous Raman. c) Suffers from fluorescence interference, because CARS signal is at high frequency. d) Faster, more efficient imaging for real-time analysis. e) Higher resolution than spontaneous Raman microscopy.arrow_forwardDraw the major product of the Claisen condensation reaction between two molecules of this ester. Ignore inorganic byproducts. Incorrect, 5 attempts remaining 1. NaOCH3/CH3OH 2. Acidic workup Select to Draw O Incorrect, 5 attempts remaining The total number of carbons in the parent chain is incorrect. Review the reaction conditions including starting materials and/or intermediate structures and recount the number of carbon atoms in the parent chain of your structure. OKarrow_forwardUsing a cell of known pathlength b = 1.25115 x 10-3 cm, a water absorption spectrum was measured. The band at 1645 cm-1, assigned to the O-H bending, showed an absorbance, A, of 1.40. a) Assuming that water density is 1.00 g/mL, calculate the water molar concentration c (hint: M= mole/L) b) Calculate the molar absorptivity, a, of the 1645 cm-1 band c) The transmitted light, I, can be written as I= Ioexp(-xb), where x is the absorption coefficient (sometimes designated as alpha), Io is the input light, and b is the cell pathlength. Prove that x= (ln10)*x*c d) Calculate x for the 1645 cm-1 bandarrow_forward
- ChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage LearningChemistryChemistryISBN:9781259911156Author:Raymond Chang Dr., Jason Overby ProfessorPublisher:McGraw-Hill EducationPrinciples of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning
- Organic ChemistryChemistryISBN:9780078021558Author:Janice Gorzynski Smith Dr.Publisher:McGraw-Hill EducationChemistry: Principles and ReactionsChemistryISBN:9781305079373Author:William L. Masterton, Cecile N. HurleyPublisher:Cengage LearningElementary Principles of Chemical Processes, Bind...ChemistryISBN:9781118431221Author:Richard M. Felder, Ronald W. Rousseau, Lisa G. BullardPublisher:WILEY





