The pKa of phenol (C6H5OH) is approximately 10, while that of aliphatic alcohol is around 16. This difference is due to:

The correct answer is B: Resonance stabilization of phenoxide ion through benzene ring. Phenoxide ion is stabilized by resonance with the benzene ring, making phenol more acidic than aliphatic alcohols.

According to the latest JEE chemistry pattern (2024-25), the conductivity of a strong electrolyte solution depends primarily on:

The correct answer is B: Concentration, nature of electrolyte, temperature, and nature of solvent. Conductivity (κ) depends on multiple factors: concentration of ions, mobility of ions (which depends on electrolyte nature, temperature, and solvent nature). These are the primary factors affecting conductivity measurements.

In electroplating of iron with copper, which electrode should be made of copper?

The correct answer is B: Anode. The anode is made of copper (the plating metal) which gets oxidized and dissolved, while the cathode (iron object) receives Cu²⁺ ions that are reduced to form the copper coating.

The relationship between standard Gibbs free energy change (ΔG°) and equilibrium constant (K) at 25°C is best represented by:

The correct answer is D: ΔG° = -RT ln K. The fundamental relationship is ΔG° = -RT ln K. Option A is equivalent when converting to log₁₀: ΔG° = -2.303RT log K. Both are correct, but D is the most fundamental form.

For electrodeposition of copper using 1 Faraday of charge, how many moles of Cu are deposited? Cu²⁺ + 2e⁻ → Cu

The correct answer is B: 0.5 mol. Cu²⁺ requires 2 electrons per atom. 1 Faraday = 1 mol of electrons; moles of Cu = 1/2 = 0.5 mol

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JEE Chemistry
Electrochemistry

Chemistry questions for JEE Main — Physical, Organic, Inorganic Chemistry.

29 Q 5 Topics Take Mock Test

Difficulty: All Easy Medium Hard 1–10 of 29

Topics in JEE Chemistry

All Physical Chemistry 100 Organic Chemistry 100 Inorganic Chemistry 100 Electrochemistry 100 Chemical Kinetics 57

Q.1 Easy Electrochemistry

Which factor does NOT significantly affect the conductance of an electrolytic solution?

A Nature of the solute

B Concentration of the solution

C Color of the solution

D Temperature of the solution

Correct Answer: C. Color of the solution

EXPLANATION

Color of a solution is a physical property unrelated to ionic conductance. Conductance depends on nature of solute, concentration, temperature, and solvent.

Test

Q.2 Easy Electrochemistry

The electrochemical series is based on which property?

A Atomic number of elements

B Standard reduction potentials

C Atomic mass of elements

D Electronegativity values

Correct Answer: B. Standard reduction potentials

EXPLANATION

The electrochemical series arranges elements in order of their standard reduction potentials, with more positive values indicating stronger oxidizing agents.

Test

Q.3 Easy Electrochemistry

What is the effect of temperature on the conductivity of ionic solutions?

A Conductivity decreases with increase in temperature

B Conductivity increases with increase in temperature

C Conductivity remains constant with temperature

D Temperature has no effect on ionic mobility

Correct Answer: B. Conductivity increases with increase in temperature

EXPLANATION

Conductivity increases with temperature because ionic mobility increases due to decreased viscosity of the medium.

Test

Q.4 Easy Electrochemistry

The standard reduction potential of H⁺/H₂ electrode is taken as 0.00 V because:

A Hydrogen is the most abundant element

B It serves as a reference electrode for all other half-cells

C Hydrogen has zero atomic number

D It's the easiest element to oxidize

Correct Answer: B. It serves as a reference electrode for all other half-cells

EXPLANATION

SHE (Standard Hydrogen Electrode) is the arbitrary reference against which all other reduction potentials are measured.

Test

Q.5 Easy Electrochemistry

In a Daniel cell, the mass of zinc electrode decreases and copper electrode increases. This indicates:

A Zn acts as anode and Cu as cathode

B Both electrodes are anodes

C Both electrodes are cathodes

D Cu acts as anode and Zn as cathode

Correct Answer: A. Zn acts as anode and Cu as cathode

EXPLANATION

Anode undergoes oxidation (Zn → Zn²⁺ + 2e⁻), losing mass. Cathode undergoes reduction (Cu²⁺ + 2e⁻ → Cu), gaining mass.

Test

Q.6 Easy Electrochemistry

In the electrolysis of molten NaCl using inert electrodes, what is produced at the cathode?

A Cl₂ gas

B Na metal

C O₂ gas

D NaOH solution

Correct Answer: B. Na metal

EXPLANATION

At cathode: Na⁺ + e⁻ → Na (reduction). At anode: 2Cl⁻ → Cl₂ + 2e⁻ (oxidation).

Test

Q.7 Easy Electrochemistry

The conductivity of a solution decreased upon dilution. This is because:

A Molar conductivity remains constant

B Number of ions per unit volume decreases

C Degree of ionization increases

D Ionic mobility increases significantly

Correct Answer: B. Number of ions per unit volume decreases

EXPLANATION

Conductivity (κ) = concentration × molar conductivity. Upon dilution, concentration decreases faster than molar conductivity increases.

Test

Q.8 Easy Electrochemistry

Which electrodes combination gives the maximum EMF in a galvanic cell at 25°C?

A Zn-Cu (E°Zn/Zn²⁺ = -0.76 V, E°Cu/Cu²⁺ = +0.34 V)

B Zn-Ag (E°Zn/Zn²⁺ = -0.76 V, E°Ag/Ag⁺ = +0.80 V)

C Fe-Cu (E°Fe/Fe²⁺ = -0.44 V, E°Cu/Cu²⁺ = +0.34 V)

D Pb-Cu (E°Pb/Pb²⁺ = -0.13 V, E°Cu/Cu²⁺ = +0.34 V)

Correct Answer: B. Zn-Ag (E°Zn/Zn²⁺ = -0.76 V, E°Ag/Ag⁺ = +0.80 V)

EXPLANATION

Maximum EMF = E°cathode - E°anode = 0.80 - (-0.76) = 1.56 V for Zn-Ag cell.

Test

Q.9 Easy Electrochemistry

In a galvanic cell, if the standard cell potential E°cell is negative, which statement is true?

A The reaction is spontaneous and ΔG° is negative

B The reaction is non-spontaneous and ΔG° is positive

C The cell will not produce any electrical energy

D The cathode potential is greater than anode potential

Correct Answer: B. The reaction is non-spontaneous and ΔG° is positive

EXPLANATION

Negative E°cell indicates non-spontaneous reaction with positive ΔG°. The relationship is ΔG° = -nFE°cell.

Test

Q.10 Easy Electrochemistry

In the electrochemical series, which metal is most easily oxidized?

A Cu

B Ag

C K

D Au

Correct Answer: C. K

EXPLANATION

Potassium (K) has the most negative standard reduction potential and is most easily oxidized among the given options. The order of ease of oxidation is K > Cu > Ag > Au.

Test

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