- Amal Augustine
- February 10, 2026
Charge Mass Relation Electrochemistry MCQs – Faraday’s Laws Numericals for Class 12
Charge mass relation electrochemistry mcqs is a key focus area for aspirants studying electrochemistry, especially at the Class 12 level and for competitive exams like NEET and JEE. Understanding how electric charge directly controls the mass of a substance deposited or liberated during electrolysis is fundamental to mastering numerical problems in this chapter.
At the heart of electrochemical calculations lies Faraday’s first law of electrolysis, which states that the mass of a substance deposited at an electrode is directly proportional to the quantity of electricity passed through the electrolyte. This principle forms the conceptual base for charge mass relation electrochemistry mcqs, where aspirants are expected to connect electrical charge with measurable chemical change.
Faraday expressed this relationship mathematically as
m ∝ Q
where m is the mass deposited and Q is the electric charge. Introducing the proportionality constant, this becomes
m = ZQ,
where Z is the electrochemical equivalent of the substance. Almost every numerical problem linked to charge mass relation electrochemistry mcqs is derived from this simple but powerful equation.
Electric charge itself is expressed as the product of current and time:
Q = It.
This means that increasing the current or allowing the electrolysis to run for a longer time increases the total charge passed, and therefore increases the mass deposited. In charge mass relation electrochemistry mcqs, questions often test whether aspirants can correctly manipulate these variables and apply the correct units.
Faraday’s second law further refines the charge–mass connection by introducing the concept of equivalent weight. According to this law, when the same quantity of electricity passes through different electrolytes, the masses deposited are proportional to their chemical equivalent weights. This is why charge mass relation electrochemistry mcqs frequently involve comparisons between two metals deposited using the same charge.
The equivalent weight depends on the atomic mass and oxidation state of the ion. Metals with lower valency deposit more mass for the same charge compared to metals with higher valency. Recognizing this trend is crucial for solving charge mass relation electrochemistry mcqs accurately and efficiently.
Another important application of the charge–mass relationship is in electroplating and metal refining. Industrial processes rely on precise control of charge to achieve uniform coating thickness. Many conceptual charge mass relation electrochemistry mcqs are framed around real-life scenarios such as electroplating, refining, and electrolysis of molten salts.
The concept also extends to gases liberated during electrolysis, such as hydrogen and oxygen. Since gas volumes can be related back to moles and electrons transferred, charge mass relation electrochemistry mcqs often integrate stoichiometry with Faraday’s laws. This makes them multi-step problems that test both chemical understanding and numerical accuracy.
Aspirants commonly make mistakes in unit conversion—mixing coulombs, faradays, seconds, and amperes. Mastery of unit consistency is essential for avoiding errors in charge mass relation electrochemistry mcqs. One faraday corresponds to approximately 96,500 coulombs and represents one mole of electrons transferred.
Another recurring theme in charge mass relation electrochemistry mcqs is series electrolysis, where the same current passes through multiple electrolytic cells. In such cases, the charge remains constant across cells, while the deposited mass depends on equivalent weight. This concept strongly reinforces the universality of the charge–mass relationship.
From a learning perspective, charge mass relation electrochemistry mcqs help bridge theoretical electrochemistry and practical calculations. They train aspirants to interpret chemical equations in terms of electron flow, rather than just reactants and products.
In exam preparation, repeated practice of charge mass relation electrochemistry mcqs improves speed, accuracy, and conceptual clarity. These problems are not about memorization but about understanding proportionality, stoichiometry, and electron balance.
Charge Mass Relation Electrochemistry MCQs with Solved Answers
1. What is the electrochemical equivalent (in g C⁻¹) of silver? (Ag = 108, F = Faraday)
a) F108\frac{F}{108}
b) 108F\frac{108}{F}
c) 108F
d) 1108F\frac{1}{108F}
Answer: b
2. A 200 W, 100 V bulb is connected in series with an electrolytic cell. If an aqueous solution of an Sn-salt is electrolyzed for 5 hours, 11.1 g of Sn gets deposited. The chemical formula of the compound is:
a) SnO
b) SnCl₄
c) SnCl₂
d) SnO₂
Answer: b
3. How much current is required to produce H₂ gas at the rate of 1 cc s⁻¹ under STP?
a) 33 A
b) 60 A
c) 7.9 A
d) 8.61 A
Answer: d
4. When a current of 10 A is passed through molten AlCl₃ for 1.608 minutes, the mass of Al deposited will be:
a) 0.09 g
b) 0.81 g
c) 1.35 g
d) 0.27 g
Answer: a
5. An electric current is passed through silver and water voltmeters in series. The cathode of silver voltmeter gains 0.054 g. The volume of O₂ liberated is:
a) 5.6 cm³
b) 11.2 cm³
c) 22.4 cm³
d) 2.8 cm³
Answer: d
6. The volume of H₂ obtained at STP when Mg obtained by passing 0.5 A through molten MgCl₂ for 32.2 min is treated with excess dilute HCl is approximately:
a) 5.6 cm³
b) 28 cm³
c) 56 cm³
d) 112 cm³
Answer: d
7. When the same quantity of current passes through CuSO₄ and AgNO₃ solutions, 2.7 g of silver is deposited. The amount of copper deposited is:
a) 0.4 g
b) 1.6 g
c) 3.2 g
d) 0.8 g
Answer: d
8. How many grams of cobalt will be deposited when CoCl₂ is electrolyzed with 10 A for 109 min?
a) 4.0 g
b) 20.0 g
c) 6.0 g
d) 0.66 g
Answer: b
9. When 965 C of electricity is passed through AgNO₃, the amount of Ag deposited is:
a) 1.08 g
b) 2.16 g
c) 10.8 g
d) 0.54 g
Answer: a
10. How many Faradays are needed for reduction of 2.5 moles of Cr₂O₇²⁻ to Cr³⁺?
a) 15
b) 12
c) 6
d) 3
Answer: a
11. Time required to deposit Cu (0.01 cm thick) on both sides of a 1×2 cm² plate using 1.5 A:
a) 4 s
b) 80 s
c) 400 s
d) 160 s
Answer: c
12. When equal electricity is passed, which metal deposits maximum mass?
a) ZnSO₄
b) FeCl₃
c) AgNO₃
d) NiCl₂
Answer: c
13. Quantity of electricity (in F) required to reduce 5 mol of MnO₄⁻:
a) 5
b) 10
c) 25
d) 30
Answer: c
14. A current of 0.5 A is passed for 30 min through CuSO₄. Mass of Cu deposited:
a) 3.18 g
b) 0.318 g
c) 0.296 g
d) 0.150 g
Answer: c
15. Number of Cu atoms deposited by 1 F of charge:
a) 6.02×10²³
b) 3.01×10²³
c) 6.02×10²²
d) 3.01×10²²
Answer: b
16. Charge required to liberate one gram-equivalent is:
a) 96500 F
b) 1 F
c) 1 C
d) None
Answer: b
17. Weak electrolyte among the following:
a) NaCl
b) HCl
c) CH₃COOH
d) K₂SO₄
Answer: c
18. Passing 1 F through CuSO₄ deposits copper equal to its:
a) Gram equivalent weight
b) Molecular weight
c) Atomic weight
d) Electrochemical weight
Answer: a
19. Time required to coat Ag (80 cm², 0.005 mm thick) using AgNO₃ (ρ = 10.5 g cm⁻³):
a) 125.1 s
b) 12.5 s
c) 155.2 s
d) 200 s
Answer: a
20. Coulombs needed to deposit 108 g Ag:
a) 96500
b) 48250
c) 193000
d) 10000
Answer: a
21. 2 A for 5 h deposits 22.2 g metal (A.W. = 177). Oxidation state is:
a) 1
b) 2
c) 4
d) 3
Answer: d
22. Mass deposited by 1 F equals:
a) Relative equivalent weight
b) Gram equivalent weight
c) Specific equivalent weight
d) None
Answer: b
23. 1 A for 16 min 5 s deposits all Cu from 1 L CuCl₂. Strength is:
a) 0.01 N
b) 0.02 M
c) 0.01 M
d) 0.2 N
Answer: a
24. Initial [Ag⁺] if 100 mL solution electrolyzed with 1.25 mA for 15 min:
a) 2.32×10⁻⁶
b) 2.32×10⁻⁴
c) 2.32×10⁻²
d) 1.16×10⁻⁴
Answer: d
25. Ratio of Ag:Cu deposited when 1 C passes through AgNO₃ and CuSO₄ (conc. 1:2):
a) 107.9 : 63.54
b) 54 : 31.77
c) 107.9 : 31.77
d) 54.31 : 31.77
Answer: c
26. Charge required to convert 1 mol MnO₄⁻ to Mn²⁺:
a) 482500 C
b) 193000 C
c) 96500 C
d) 36500 C
Answer: a
27. 4.5 g Al deposited from Al³⁺. Volume of H₂ at STP by same charge:
a) 44.8 L
b) 11.2 L
c) 22.4 L
d) 5.6 L
Answer: d
28. Weight of Cu deposited by 2 F charge:
a) 317.5 g
b) 23.85 g
c) 63.5 g
d) 127 g
Answer: c
29. One litre of 1 M CuSO₄ electrolyzed with 2 F. Final molarity is:
a) M
b) 2M
c) 4M
d) Zero
Answer: d
30. 2×10⁻⁵ C charge on Zn²⁺ corresponds to:
a) 2×10⁻⁵ mol Zn²⁺
b) 6.22×10⁷ Zn²⁺ ions
c) 0.64 mg Zn²⁺
d) 1×10⁻¹⁰ mol Zn²⁺
Answer: c
Conclusion on Charge Mass Relation Electrochemistry MCQs
In conclusion, charge mass relation electrochemistry mcqs represent a cornerstone of electrochemistry numericals. By focusing on the relationship between charge, mass, and equivalent weight, students gain a deeper insight into how electrical energy drives chemical change. Strong command over this charge mass relation electrochemistry mcqs topic ensures confidence in solving a wide range of electrochemical problems across academic and competitive examinations.
Amal Augustine is the founder of ExQuizMe, a dynamic learning and quiz platform built to make education engaging, competitive, and fun. A passionate learner and an academic achiever, Amal completed his schooling at Government HSS Manjapra, graduating with 92.5% in Computer Science. He later earned his degree from St. Stephen’s College, University of Delhi, one of India’s most prestigious arts and science institutions.
Currently, Amal is pursuing his Master’s degree at National Sun Yat-sen University, Taiwan, where he continues to deepen his interest in research and technology. Throughout his school and college years, he won 50+ national-level interschool and collegiate quiz competitions, was
Beyond academics, Amal Augustine is an avid reader of science journals, a dedicated research student, and a technology enthusiast who loves programming and exploring the world of Computer Science. Through ExQuizMe, he aims to make learning accessible, enjoyable, and empowering for students across the globe.