9.2.1 Standard Electrode Potential (Q&A)

Short Answer Questions

1. What is electrode potential?
   Answer
   Electrode potential is a measure of the tendency of a chemical species to either lose or gain electrons when immersed in a solution, determining its likelihood to undergo oxidation or reduction.
   
2. In what unit is electrode potential measured?
   Answer
   Electrode potential is measured in volts (V).
   
3. What does a higher electrode potential indicate about a metal?
   Answer
   A higher electrode potential indicates that a metal is less likely to release electrons and form positive ions.
   
4. What is standard electrode potential (E°)?
   Answer
   Standard electrode potential (E°) is the electrode potential of a half-cell measured under standard conditions.
   
5. List the standard conditions for measuring standard electrode potential.
   Answer
   1. Temperature of 298 K (25°C)
   2. 1.0 mol dm⁻³ concentration for solutions
   3. Pressure of 1 atm (101 kPa) for gases
   
6. What is the function of the Standard Hydrogen Electrode (SHE)?
   Answer
   The Standard Hydrogen Electrode (SHE) is used as the primary reference point for measuring all other electrode potentials.
   
7. What is the standard electrode potential of the SHE?
   Answer
   The standard electrode potential of the SHE is exactly 0.00 V.
   
8. Write the half-equation for the Standard Hydrogen Electrode.
   Answer
   2H⁺(aq) + 2e⁻ ⇌ H₂(g)
   
9. How can electrode potentials be used to determine redox strength?
   Answer
   Electrode potentials help determine the relative strengths of oxidizing and reducing agents. More positive E° values indicate strong oxidizing agents, while more negative E° values indicate strong reducing agents.
   
10. Give an example of a strong oxidizing agent based on its E° value.
    Answer
    F₂/F⁻ with an E° value of +2.87 V is the strongest oxidizing agent.
    
11. What does a more negative E° value indicate about a species?
    Answer
    A more negative E° value indicates that a species is a strong reducing agent, meaning it has a higher tendency to lose electrons and undergo oxidation.
    
12. What is the electrochemical series?
    Answer
    The electrochemical series is a list of half-reactions arranged in order of their standard electrode potentials.
    
13. How does the electrochemical series help predict redox reactions?
    Answer
    The series helps determine which species will undergo oxidation (anode) and which will undergo reduction (cathode) based on their E° values.
    
14. How is standard cell potential (E°cell) calculated?
    Show More
    E°cell = E°cathode – E°anode
    
15. What does a positive E°cell value indicate?
    Answer
    A positive E°cell value indicates that the redox reaction is spontaneous under standard conditions.
    
16. List two factors that affect electrode potential.
    Answer
    1. Ion concentration
    2. Temperature
17. What happens to electrode potential when ion concentration increases?
    Answer
    Increasing ion concentration usually makes the electrode potential more positive.
    
18. What is the E° value for the Zn²⁺/Zn half-reaction?
    Answer
    The E° value for Zn²⁺ + 2e⁻ ⇌ Zn is -0.76 V.
    
19. Name one industrial application of standard electrode potentials.
    Answer
    Electroplating
20. Which metal acts as the strongest reducing agent in the electrochemical series?
    Answer
    Lithium (Li) is the strongest reducing agent with an E° value of -3.04 V.

Explanation Questions

1. Why does a higher electrode potential mean a species is a stronger oxidizing agent?
   Answer
   A higher electrode potential means the species has a greater tendency to gain electrons and undergo reduction, making it a stronger oxidizing agent.
   
2. Explain why the SHE is important in electrochemistry.
   Answer
   The SHE provides a universal reference point (0.00 V) for comparing electrode potentials, allowing scientists to measure redox tendencies consistently.
   
3. How does temperature affect electrode potential?
   Answer
   Changes in temperature can alter the equilibrium position of the redox reaction, influencing the electrode potential.
   
4. Why does Zn/Zn²⁺ have a negative E° value?
   Answer
   Zinc has a high tendency to lose electrons and form Zn²⁺, making it a strong reducing agent with a negative electrode potential.
   
5. How does the electrochemical series predict the spontaneity of redox reactions?
   Answer
   If the E°cell value (E°cathode – E°anode) is positive, the reaction is spontaneous.
   
6. Why does increasing ion concentration make electrode potential more positive?
   Answer
   Higher ion concentration shifts equilibrium towards reduction, increasing the electrode potential.
   
7. Why does Cl₂/Cl⁻ have a high E° value?
   Answer
   Chlorine has a strong tendency to accept electrons, making it a powerful oxidizing agent with a high E° value.
   
8. What happens if E°cell is negative?
   Answer
   A negative E°cell value indicates a non-spontaneous reaction under standard conditions.
   
9. How does E°cell relate to battery voltage?
   Answer
   E°cell determines the maximum voltage a battery can produce under standard conditions.
   
10. Why do different electrodes have different E° values?
    Answer
    Each metal has a unique tendency to gain or lose electrons, affecting its standard electrode potential.