ElectrochemistryNEET MCQs with solutions
Electrochemistry covers electrochemical cells (galvanic and electrolytic), Nernst equation, conductivity, molar conductivity, Kohlrausch's law, Faraday's laws of electrolysis and corrosion. NEET tests Nernst equation calculations, EMF of cells, and Faraday's law problems — both conceptual and numerical.
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- 12 Chemistry
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Tap an option to check it. Questions from every NCERT topic in this chapter, from easy to hard.
Q1Important PYQ Mixed Concepts
The molar conductivity of a 0.050 mol L⁻¹ monobasic weak acid solution is 90 S cm² mol⁻¹. If limiting ionic conductivities are 349.6 and 50.4 S cm² mol⁻¹, the degree of dissociation is:
Not quite — the answer is A.
At infinite dilution, Λ°m = 349.6 + 50.4 = 400 S cm² mol⁻¹. Degree of dissociation α = Λm/Λ°m = 90/400 = 0.225. Options B, C and D result from arithmetic errors such as using wrong Λ°m values or incorrect formula application.
Q2Corrosion
Which of the following correctly defines corrosion according to NCERT?
Not quite — the answer is A.
Corrosion is the electrochemical oxidation of metals by environmental agents (O₂, H₂O, CO₂). It is not combustion (too rapid) nor reduction (metals are oxidised, not reduced) during corrosion.
Q3Conductance and Conductivity
Conductance of a conductor is defined as
Not quite — the answer is A.
Conductance G = 1/R (S). Option D defines conductance indirectly via Ohm's law but current/voltage ratio gives conductance only when R=1Ω — not a definition. Option A is the direct NCERT definition.
Q4Electrolysis and Faraday Laws
Faraday's first law states that the mass deposited during electrolysis is proportional to
Not quite — the answer is A.
m = ZQ = ZIt; mass depends on total charge (Q = It), not temperature, solvent, or area. The trap is "molecular weight" — students confuse it with equivalent weight, which appears in Faraday's second law, not the first.
Q5Ultimate Revision
Which of the following conditions makes a galvanic cell reaction non-spontaneous?
Not quite — the answer is A.
A spontaneous galvanic cell requires Ecell > 0 and ΔG < 0. When Ecell < 0, ΔG = −nFE becomes positive, confirming non-spontaneity. Option C is the trap — ΔG < 0 is the spontaneity condition, not the non-spontaneity condition.
Q6Electrochemical Cells
Which electrode acts as the anode in a galvanic cell?
Not quite — the answer is A.
Anode is defined as the electrode where oxidation occurs — electrons are released here and flow through the external circuit to the cathode. The sign (negative) follows from this electron release.
Q7Electrode Potential
Standard conditions for measuring standard electrode potential are
Not quite — the answer is A.
NCERT specifies 1 bar (not 1 atm) and 298 K as standard conditions; 1 atm ≈ 1.013 bar, making Option B a common trap. Option D pairs atm with 298 K — wrong pressure unit. Standard temperature is 298 K, not 273 K.
Q8Applications of Electrochemistry
In electroplating, the object to be coated is connected as which electrode?
Not quite — the answer is B.
The object to be plated is the cathode; metal ions from the solution deposit on it by reduction. The anode is the source metal that oxidizes to replenish ions. Connecting it as anode would dissolve the object instead.
Q9Batteries
Which of the following is used as the electrolyte in a dry cell (Leclanché cell)?
Not quite — the answer is A.
The dry cell uses a moist paste of NH₄Cl and ZnCl₂ as electrolyte — not a liquid. H₂SO₄ is used in lead storage batteries. KOH is the electrolyte in mercury and alkaline cells.
Q10Mixed Revision
A cell reaction has E°cell = 0.0591 V and involves transfer of 2 electrons. The equilibrium constant K at 298 K is:
Not quite — the answer is B.
Using log K = nE°cell/0.0591 = (2×0.0591)/0.0591 = 2, hence K = 10². Options A, C and D do not satisfy this relation.
Q11Nernst Equation
The Nernst equation shows that cell potential depends on E° and
Not quite — the answer is C.
Nernst: E = E° − (RT/nF)ln Q. Q contains ion concentrations; R, T, F are constants with T appearing explicitly. Pressure and mass of electrodes do not appear in the equation.
Q12Numericals Electrochemistry
For a cell with E° = 1.10 V, calculate Ecell at 298 K when Q = 1.
Not quite — the answer is A.
When Q = 1, ln Q = 0, so the Nernst correction term = 0; therefore Ecell = E° = 1.10 V regardless of n. Option B halves E° incorrectly. Option C subtracts 0.0591 without basis (log 1 = 0, not 1).
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Get RankUp on Google PlayQ13Grand Test
A solution containing Cu(NO₃)₂, AgNO₃ and Hg₂(NO₃)₂ is electrolysed. Given E°(Ag⁺/Ag)=+0.80V, E°(Hg₂²⁺/Hg)=+0.79V, E°(Cu²⁺/Cu)=+0.34V, the deposition order at the cathode with increasing applied voltage is:
Not quite — the answer is A.
Species with more positive reduction potential is preferentially reduced. Ag⁺ (+0.80V) deposits first, then Hg₂²⁺ (+0.79V), then Cu²⁺ (+0.34V) last. More voltage must be applied to reduce the less positive species.
Q14Redox Reactions and Oxidation Number Basics
Which statement correctly defines oxidation in terms of electron transfer?
Not quite — the answer is A.
Oxidation is defined as loss of electrons (OIL — Oxidation Is Loss). Gain of electrons is reduction. Protons and neutrons are not involved in redox definitions.
Q15Mixed Electrochemistry
At which condition does the EMF of a cell become exactly zero?
Not quite — the answer is A.
At equilibrium Q = K, so ln(Q/K) = 0, making Ecell = 0 by Nernst equation. Option B is wrong because high temperature alone does not set Q = K unless equilibrium is reached. Option D affects current flow, not EMF.
Q16Redox Reactions and Oxidation Number Basics
In a redox reaction, the substance that gains electrons is called the:
Not quite — the answer is A.
The substance that gains electrons is reduced, and by definition acts as the oxidising agent. A reducing agent loses electrons (gets oxidised). Catalysts and spectator ions do not undergo electron transfer.
Q17Redox Reactions and Oxidation Number Basics
The oxidation number of oxygen in H₂O₂ is:
Not quite — the answer is C.
In peroxides (O–O bond), oxygen has oxidation number -1, not the usual -2. This is a direct NCERT exception. Option A (-2) is the most common wrong choice.
Q18Redox Reactions and Oxidation Number Basics
Identify the oxidising agent in: Zn + Cu²⁺ → Zn²⁺ + Cu
Not quite — the answer is D.
Cu²⁺ gains electrons and is reduced to Cu, making it the oxidising agent. Zn loses electrons and is oxidised, making it the reducing agent.
Q19Redox Reactions and Oxidation Number Basics
Which of the following correctly links oxidation number change to the process of oxidation?
Not quite — the answer is B.
Oxidation = increase in oxidation number = loss of electrons. Option C is the classic trap: students confuse increase in oxidation number with electron gain (which is actually reduction).
Q20Redox Reactions and Oxidation Number Basics
Which species has the highest oxidation state of sulfur among the following?
Not quite — the answer is B.
In SO₄²⁻, sulfur is +6 (highest). H₂S = -2, SO₂ = +4, S₂O₃²⁻ = +2 average. S₂O₃²⁻ is a strong trap as students may confuse it with SO₄²⁻.
Q21Redox Reactions and Oxidation Number Basics
In the reaction Fe²⁺ → Fe³⁺, the process occurring is:
Not quite — the answer is C.
Fe²⁺ loses one electron to become Fe³⁺ — oxidation number increases from +2 to +3, which is oxidation. Reduction would require a decrease in oxidation number.
Q22Redox Reactions and Oxidation Number Basics
Which of the following is a redox reaction?
Not quite — the answer is D.
Only Zn + HCl involves electron transfer: Zn (0→+2) and H (+1→0). Options A, B, C are ionic/combination reactions with no change in oxidation numbers.
Q23Redox Reactions and Oxidation Number Basics
The oxidation number of chlorine in ClO₃⁻ is:
Not quite — the answer is A.
Using x + 3(−2) = −1: x = +5. Options +3 and +1 are traps for students who miscalculate the ion charge or count oxygen incorrectly.
Q24Redox Reactions and Oxidation Number Basics
Which of the following statements about a reducing agent is correct?
Not quite — the answer is B.
A reducing agent loses electrons and thereby gets oxidised (increases its own oxidation number). Option A is the classic confusion with oxidising agent behaviour.
ELITE question · AIR under 50 level
This chapter has 352 ELITE questions for students aiming at the very top. They are only in the app.
Unlock ELITE questions in the appKey Electrochemistry Concepts
Quick revision: most questions in this chapter test these facts.
| Concept | Key Fact |
|---|---|
| Galvanic cell | Spontaneous; anode (−, oxidation) || cathode (+, reduction); E°cell > 0 |
| Nernst equation | E = E° − (RT/nF)ln Q; at 25°C: E = E° − (0.0591/n)log Q |
| Conductivity (κ) | κ = 1/ρ; units: S cm⁻¹; increases with dilution for weak electrolytes |
| Kohlrausch's law | Λ°m = λ°(cation) + λ°(anion); used to find Λ°m of weak electrolytes |
| Faraday's laws | m = (M·I·t)/(n·F); F = 96485 C/mol; 1 Faraday deposits 1 equivalent |
| Corrosion | Electrochemical process; iron rusts at anode (Fe→Fe²⁺), O₂ reduced at cathode |
What the app covers in this chapter
890 questions in total, each with a detailed explanation.
| Important PYQ Mixed Concepts | 109 |
| Corrosion | 62 |
| Conductance and Conductivity | 61 |
| Electrolysis and Faraday Laws | 61 |
| Ultimate Revision | 61 |
| Electrochemical Cells | 60 |
| Electrode Potential | 60 |
| Applications of Electrochemistry | 60 |
| Batteries | 60 |
| Mixed Revision | 60 |
| Nernst Equation | 59 |
| Numericals Electrochemistry | 59 |
| Grand Test | 59 |
| Redox Reactions and Oxidation Number Basics | 39 |
| Mixed Electrochemistry | 20 |
Questions students ask
Is Electrochemistry important for NEET?
Very important — Nernst equation, EMF calculations, Faraday's laws and conductivity are tested every year. It is one of the highest-weightage Physical Chemistry chapters.
Which topics should I revise first?
Focus on Nernst equation calculations, galvanic cell conventions (anode/cathode, salt bridge), Kohlrausch's law application, Faraday's law problems, and the electrochemical theory of corrosion.
How many questions from this chapter are on RankUp?
The RankUp app has 890 questions on Electrochemistry, including 352 ELITE questions. Every question has a detailed explanation.
