JEE Chemistry — MCQ Practice Questions & Answers

Question 1

Which of the following is the SI unit of electrical conductivity?

Accepted Answer

Correct answer: A. S·m⁻¹ — Electrical conductivity is measured in Siemens per meter (S·m⁻¹). Ω·m is the unit of resistivity, which is the reciprocal of conductivity.

Answer

B. Ω·m

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C. A·V⁻¹

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D. S·m²

Question 2

In a galvanic cell, which electrode acts as the anode?

Accepted Answer

Correct answer: B. The electrode where oxidation occurs — In a galvanic cell, oxidation occurs at the anode. The anode is the negative electrode where electrons are released.

Answer

A. The electrode where reduction occurs

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C. The electrode connected to the positive terminal

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D. The electrode made of inert material

Question 3

What is the charge on one mole of electrons?

Accepted Answer

Correct answer: C. 96485 C — One mole of electrons carries a charge equal to Faraday's constant, which is approximately 96485 C/mol or 96500 C/mol.

Answer

A. 1.6 × 10⁻¹⁹ C

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B. 6.022 × 10²³ C

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D. 1.6 × 10⁻¹⁹ × 6.022 × 10²³ C

Question 4

The Nernst equation relates cell potential to concentration. At 25°C, which form is correct?

Accepted Answer

Correct answer: C. E = E° + (0.0592/n) log Q — The Nernst equation at 25°C is E = E° + (0.0592/n) log Q, where Q is the reaction quotient and n is the number of electrons transferred.

Answer

A. E = E° + (0.059/n) log Q

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B. E = E° - (0.0592/n) log Q

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D. E = E° - (0.059/n) log(1/Q)

Question 5

Which of the following statements about electrolysis is INCORRECT?

Accepted Answer

Correct answer: B. In electrolysis, oxidation occurs at the cathode — In electrolysis, oxidation occurs at the ANODE, not the cathode. The cathode is where reduction occurs. At the anode, electrons are removed from species.

Answer

A. Electrolysis is a non-spontaneous process

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C. Electrical energy drives the electrolysis reaction

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D. The anode in electrolysis is positively charged

Question 6

A metal X is more easily oxidized than metal Y. If X and Y form a galvanic cell, which metal acts as the anode?

Accepted Answer

Correct answer: A. Metal X (anode) — The metal that is more easily oxidized (more reactive) acts as the anode. Metal X, being more reactive, loses electrons and acts as the anode (negative electrode).

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B. Metal Y (anode)

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C. Depends on the electrolyte used

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D. Both metals act as anodes

Question 7

The standard cell potential for a reaction is -0.5 V. What can be concluded about this reaction?

Accepted Answer

Correct answer: D. Both B and C are correct — A negative E° (E°cell < 0) indicates a non-spontaneous reaction under standard conditions. ΔG° = -nFE°, so negative E° gives positive ΔG°.

Answer

A. The reaction is spontaneous under standard conditions

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B. The reaction is non-spontaneous under standard conditions

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C. ΔG° is positive

Question 8

In the Daniel cell, the half-cell potentials are: Cu²⁺ + 2e⁻ → Cu, E° = +0.34 V and Zn²⁺ + 2e⁻ → Zn, E° = -0.76 V. Calculate E°cell:

Accepted Answer

Correct answer: C. 1.10 V — E°cell = E°cathode - E°anode = 0.34 - (-0.76) = 0.34 + 0.76 = 1.10 V. Cu²⁺ is reduced (cathode) and Zn is oxidized (anode).

Answer

A. 0.42 V

Answer

B. 0.76 V

Answer

D. 1.34 V

JEE Chemistry - MCQ Practice Questions