Electrochemistry Quiz - ICSE Class 12 Chemistry

Free practice quiz: Electrochemistry (ICSE Class 12 Chemistry). 26 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

This ICSE Class 12 Chemistry practice quiz has 26 multiple-choice questions on Electrochemistry, and 26 of them come with an explanation. Try the 5 sample questions below (tap an option to check yourself), then play the full quiz online. No sign-up needed.

Sample questions

1. For a spontaneous electrochemical reaction, which of the following conditions must be met?

   1. ΔG > 0 and E°cell < 0
   2. ΔG < 0 and E°cell > 0
   3. ΔG = 0 and E°cell = 0
   4. ΔG > 0 and E°cell > 0
   Show answer

   Answer: B. ΔG < 0 and E°cell > 0

   A spontaneous process is characterized by a negative Gibbs free energy change (ΔG < 0). The relationship between Gibbs free energy and cell potential is given by ΔG = -nFEcell. Therefore, for a spontaneous reaction (ΔG < 0), the cell potential (Ecell) must be positive (E°cell > 0).

2. The Nernst equation relates the cell potential to:

   1. Temperature and pressure only
   2. Concentration of reactants and products
   3. Gibbs free energy and entropy
   4. Electrode material and electrolyte concentration
   Show answer

   Answer: B. Concentration of reactants and products

   The Nernst equation describes how the cell potential (Ecell) varies with the concentrations of the reacting species, temperature, and other thermodynamic parameters. Specifically, it relates Ecell to the standard cell potential (E°cell) and the reaction quotient (Q).

3. If the temperature of an electrochemical cell increases, how does the cell potential generally change?

   1. It increases if the reaction is exothermic.
   2. It decreases if the reaction is endothermic.
   3. It increases if ΔS is positive.
   4. It decreases if ΔS is negative.
   Show answer

   Answer: C. It increases if ΔS is positive.

   The relationship between cell potential (E), Gibbs free energy (ΔG), entropy (ΔS), and temperature (T) is given by ΔG = ΔH - TΔS and ΔG = -nFE. Therefore, -nFE = ΔH - TΔS. So, E = -(ΔH/nF) + (TΔS/nF). If ΔS is positive, an increase in temperature (T) leads to a more positive value of the (TΔS/nF) term, thus increasing the cell potential (E).

4. Which metal can displace hydrogen from dilute acids?

   1. Cu
   2. Ag
   3. Au
   4. Zn
   Show answer

   Answer: D. Zn

   A metal can displace hydrogen from dilute acids if it is more reactive than hydrogen. This means its standard electrode potential is more negative than that of the hydrogen electrode (0 V). Zinc (E° = -0.76 V) is above hydrogen in the electrochemical series and can displace hydrogen. Copper (E° = +0.34 V), Silver (E° = +0.80 V), and Gold (E° = +1.50 V) are below hydrogen and cannot displace hydrogen from dilute acids.

5. The relationship between standard electrode potential (E°) and the equilibrium constant (K) for a cell reaction is given by:

   1. E° = (RT/nF) ln K
   2. E° = -(RT/nF) ln K
   3. E° = (nF/RT) ln K
   4. E° = -(nF/RT) ln K
   Show answer

   Answer: A. E° = (RT/nF) ln K

   The standard Gibbs free energy change (ΔG°) is related to the standard cell potential (E°) by ΔG° = -nFE°. It is also related to the equilibrium constant (K) by ΔG° = -RTlnK. Equating these two expressions gives -nFE° = -RTlnK, which rearranges to E° = (RT/nF)lnK.

More questions in this quiz

Answers and explanations are in the full quiz.

1. Consider the electrolysis of molten NaCl. What is deposited at the cathode?
2. The molar conductivity of a strong electrolyte increases with dilution because:
3. Calculate the standard cell potential (E°cell) for the reaction: Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s), given E°(Zn²⁺/Zn) = -0.76 V and E°(Cu²⁺/Cu) = +0.34 V.
4. According to Kohlrausch's law, the molar conductivity of an electrolyte at infinite dilution is equal to:
5. What is the relationship between the equilibrium constant (K) and the standard cell potential (E°cell)?
6. Faraday's first law of electrolysis states that:
7. The electrochemical series is arranged in order of:
8. During the electrolysis of aqueous copper sulfate using copper electrodes, what happens at the anode?
9. A primary cell is one that:
10. The limiting molar conductivity of weak electrolytes can be determined using:
11. Which of the following conditions must be met for an electrochemical cell to be considered a galvanic or voltaic cell?
12. The resistance of a conductivity cell is found to be 100 Ω. If the cell constant is 0.5 cm⁻¹, what is the conductivity of the solution?
13. The passage of 1 Faraday of electricity through a solution of a salt of a bivalent metal deposits:
14. In an electrochemical cell, oxidation always occurs at the:
15. What is the unit of molar conductivity?
16. Lead-acid storage batteries are:
17. The unit of electrical resistance is:
18. Which phenomenon is responsible for the increase in molar conductivity of a strong electrolyte with dilution?
19. What is the relationship between the standard cell potential (E°cell) and the standard Gibbs free energy change (ΔG°)?
20. Which of the following metals will have the most positive standard electrode potential?
21. A standard hydrogen electrode (SHE) is defined with a standard reduction potential of:

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