Electrochemistry Practice Questions
Thanaweya Amma (Egypt) · Thanaweya Chemistry · 150 free MCQs with instant results and detailed explanations.
150
Total
48
Easy
74
Medium
28
Hard
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Sample Questions from Electrochemistry
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
Which of the following statements best describes an electrolytic cell?
A.
It converts chemical energy into electrical energy.
B.
It converts electrical energy into chemical energy.
C.
It operates spontaneously without external energy.
D.
It does not require any ionic solutions.
Show Answer & Explanation
Correct Answer: B
An electrolytic cell uses electrical energy to drive a non-spontaneous chemical reaction, making option B correct.
Q2
Easy
In the electrolysis of water, what is produced at the cathode?
A.
Oxygen gas
B.
Hydrogen gas
C.
Hydroxide ions
D.
Hydrogen peroxide
Show Answer & Explanation
Correct Answer: B
During the electrolysis of water, hydrogen gas is produced at the cathode where reduction occurs, making option B the correct answer.
Q3
Easy
What is the purpose of a salt bridge in an electrochemical cell?
A.
To increase the current flow.
B.
To maintain electrical neutrality in the half-cells.
C.
To facilitate the reaction rates.
D.
To separate the electrodes.
Show Answer & Explanation
Correct Answer: B
The salt bridge allows ions to flow between the half-cells, maintaining electrical neutrality, thus option B is correct.
Q4
Medium
What is the standard potential of a hydrogen electrode at standard conditions?
A.
0.00 V
B.
1.23 V
C.
-0.76 V
D.
0.34 V
Show Answer & Explanation
Correct Answer: A
The standard hydrogen electrode is defined to have a potential of 0.00 V under standard conditions (1 atm pressure, 25°C). This is the reference point for measuring other electrode potentials.
Q5
Medium
In a galvanic cell, if the anode reaction is Zn → Zn²⁺ + 2e⁻, what is the cathode reaction?
A.
Cu²⁺ + 2e⁻ → Cu
B.
2H⁺ + 2e⁻ → H₂
C.
Ag⁺ + e⁻ → Ag
D.
Fe²⁺ + 2e⁻ → Fe
Show Answer & Explanation
Correct Answer: A
In a galvanic cell, the anode is where oxidation occurs (Zn is oxidized), and the cathode is where reduction occurs. The most common cathode reaction paired with zinc is the reduction of copper ions (Cu²⁺) to copper (Cu).
Q6
Medium
Which of the following factors does NOT affect the cell potential of an electrochemical cell?
A.
Concentration of reactants
B.
Temperature
C.
Pressure
D.
Color of the electrodes
Show Answer & Explanation
Correct Answer: D
The color of the electrodes has no impact on the electrochemical reactions or the cell potential, while concentration, temperature, and pressure do influence the cell potential as per the Nernst equation.
Q7
Medium
If the equilibrium constant (K) for a redox reaction is 1000, what does this indicate about the standard cell potential (E°)?
A.
E° is negative
B.
E° is zero
C.
E° is positive
D.
E° cannot be determined from K
Show Answer & Explanation
Correct Answer: C
A large equilibrium constant (K = 1000) indicates that the reaction strongly favors the products, which corresponds to a positive standard cell potential (E°) according to the relationship E° = (RT/nF) ln(K).
Q8
Hard
In an electrochemical cell, if the standard reduction potential of the cathode is +0.76 V and the anode is -0.44 V, what is the standard cell potential (E°cell) for this cell?
A.
+1.20 V
B.
+0.32 V
C.
-0.32 V
D.
+0.44 V
Show Answer & Explanation
Correct Answer: A
The standard cell potential (E°cell) is calculated using E°cell = E°cathode - E°anode. Thus, E°cell = 0.76 V - (-0.44 V) = 0.76 V + 0.44 V = 1.20 V.
Q9
Hard
Which of the following statements about galvanic cells is incorrect?
A.
The anode is the site of reduction.
B.
Electrons flow from anode to cathode.
C.
Oxidation occurs at the anode.
D.
The cell converts chemical energy into electrical energy.
Show Answer & Explanation
Correct Answer: A
In galvanic cells, the anode is actually the site of oxidation, not reduction. Reduction occurs at the cathode, where electrons are accepted.
Q10
Hard
In a galvanic cell, the reduction potential of the cathode is +0.76 V, and that of the anode is -0.44 V. What is the overall cell potential (E°cell) for this galvanic cell?
A.
+1.20 V
B.
+0.32 V
C.
-1.20 V
D.
0 V
Show Answer & Explanation
Correct Answer: A
The overall cell potential is calculated by subtracting the anode potential from the cathode potential. E°cell = E°(cathode) - E°(anode) = 0.76 V - (-0.44 V) = 1.20 V. Thus, the correct answer is +1.20 V.
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Electrochemistry — Thanaweya Amma (Egypt) Thanaweya Chemistry Practice Questions Online
This page contains 150 practice MCQs for the chapter Electrochemistry in Thanaweya Amma (Egypt) Thanaweya Chemistry. The questions are organized by difficulty — 48 easy, 74 medium, 28 hard — so you can choose the right level for your preparation.
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