AP Chemistry · Topic 9.10
Electrolysis and Faraday's Law Practice
Part of Applications of Thermodynamics.(ENE-6.D)
Practice questions
22
Sample questions
5 of 22 — sign in to practice the rest with adaptive difficulty and mastery tracking.
Sample 1difficulty 2/5
The schematic shows an electrolytic cell driven by an external DC source.
In an electrolytic cell, where does reduction occur?
- Acheck_circle
At the cathode (negative electrode)
- B
In the bulk solution only
- C
At the anode (positive electrode)
- D
In the salt bridge
Why
In electrolysis the cathode is connected to the negative terminal of the power source; cations migrate there and gain electrons (reduction).
- A
Sample 2difficulty 2/5
Electrolysis is
- A
Spontaneous reaction generating current
- Bcheck_circle
Forced non-spontaneous reaction using applied current
- C
Distillation
- D
Heating a salt
Why
External voltage drives a reaction with E < 0 (or ΔG > 0).
- A
Sample 3difficulty 3/5
Electrolysis of water with inert electrodes produces
- A
No reaction
- B
H₂ at anode, O₂ at cathode
- C
Cl₂ at anode
- Dcheck_circle
H₂ at cathode, O₂ at anode
Why
Reduction (cathode) → H₂; oxidation (anode) → O₂.
- A
Sample 4difficulty 3/5
A student electroplates copper from 0.50 M CuSO4 onto a clean copper cathode. A constant current of 0.500 A is passed for 30.0 min. The cathode is dried and reweighed; the mass increases by 0.296 g. F = 96,485 C/mol e-. M(Cu) = 63.55 g/mol.
How does the experimental mass of Cu deposited compare to the theoretical mass?
- A
Theoretical = 0.296 g; experimental should be 1/2 because Cu^2+
- B
Theoretical = 0.148 g; efficiency ~200%
- Ccheck_circle
Theoretical = 0.296 g; experimental matches within rounding (~100% efficiency)
- D
Theoretical = 0.592 g; efficiency ~50%
Why
Q = It = 0.500*1800 = 900 C. mol e- = 900/96485 = 9.328e-3. mol Cu = 9.328e-3/2 = 4.664e-3. mass = 4.664e-3 * 63.55 = 0.296 g.
- A
Sample 5difficulty 3/5
During operation of a Zn|Zn²⁺ || Cu²⁺|Cu galvanic cell, what happens to electrode masses?
- Acheck_circle
Zn anode mass decreases; Cu cathode mass increases
- B
Zn gains, Cu loses
- C
Both gain mass
- D
Both electrodes lose mass
Why
Zn(s) → Zn²⁺ + 2e⁻ at the anode (mass decreases); Cu²⁺ + 2e⁻ → Cu(s) at the cathode (mass increases).
- A