Chemistry Test Electrochemistry 1 — Questions and Answers
Question 1: What is the standard reduction potential of the standard hydrogen electrode (SHE)?
- 0.00 V (Correct answer)
- +1.23 V
- -0.76 V
- +0.34 V
Correct answer: 0.00 V
The SHE is defined as having a standard reduction potential of exactly 0.00 V and serves as the reference point for all other electrode potentials.
Question 2: In a galvanic cell, oxidation occurs at which electrode?
- Cathode
- Anode (Correct answer)
- Salt bridge
- Reference electrode
Correct answer: Anode
In a galvanic (voltaic) cell, the anode is where oxidation (loss of electrons) occurs, while reduction occurs at the cathode.
Question 3: Which equation relates the Gibbs free energy change to cell potential?
- ΔG = nFE
- ΔG = -nFE (Correct answer)
- ΔG = RT ln K
- ΔG = -RT ln E
Correct answer: ΔG = -nFE
The relationship ΔG = -nFE shows that a positive cell potential (E) corresponds to a negative ΔG, indicating a spontaneous reaction.
Question 4: Faraday's constant (F) represents which quantity?
- Charge of one electron
- Charge of one mole of electrons (Correct answer)
- Avogadro's number times Planck's constant
- Molar mass of electrons
Correct answer: Charge of one mole of electrons
Faraday's constant (~96,485 C/mol) is the total electric charge carried by one mole of electrons.
Question 5: The Nernst equation is used to calculate cell potential under which conditions?
- Standard conditions only
- Non-standard conditions (Correct answer)
- At equilibrium only
- Only when temperature is 0°C
Correct answer: Non-standard conditions
The Nernst equation (E = E° - (RT/nF)ln Q) adjusts the standard cell potential for non-standard concentrations and conditions.
Question 6: Which metal is deposited at the cathode during the electrolysis of copper sulfate solution using copper electrodes?
- Sulfur
- Oxygen
- Copper (Correct answer)
- Hydrogen
Correct answer: Copper
During electrolysis of CuSO₄ with copper electrodes, Cu²⁺ ions are reduced and copper metal is deposited at the cathode.
Chemistry Test Electrochemistry 1
What is the standard reduction potential of the standard hydrogen electrode (SHE)?