Free Electrochemistry MCQs with Answers

• A. H2
• B. Cl2
• C. O2
• D. Na

Explanation: During the electrolysis of brine (a concentrated solution of sodium chloride), chloride ions (Cl-) are oxidized at the anode to form…

• A. (COOH)2
• B. F2
• C. CO2
• D. HNO3

Explanation: (COOH)2 is the correct answer because it acts as a reducing agent by donating electrons to other substances in a reaction, thereby…

• A. +2
• B. +6
• C. +4
• D. +5

Explanation: In the nitrate ion, NO3-1, each oxygen atom has an oxidation number of -2. The total contribution from three oxygen atoms is -6.

• A. C
• B. O
• C. H
• D. Both A and B

Explanation: The correct answer is Option A: C. In glucose, the element Carbon has a zero oxidation state.

• A. It is the apparent charge on an atom in a compound
• B. Its value is either zero, positive, or negative
• C. It can be variable
• D. Xenon (Xe) can show a maximum oxidation state of +6 in its compounds

Explanation: The correct answer is Option D: Xenon (Xe) can show a maximum oxidation state of +6 in its compounds.

• A. Cryolite provides the ions needed to carry current
• B. To decrease high melting point of the electrolyte
• C. Cryolite reacts with AI2O3 to form ions
• D. Molten AI2O3 would not conduct electricity

Explanation: The correct answer is B) To decrease high melting point of the electrolyte.

• A. Zero
• B. +1
• C. -1
• D. -2

Explanation: In FeCl3, chlorine is more electronegative than iron and typically gains one electron per chlorine atom to achieve a stable octet.

• A. They may be deposited or released on the electrode surface
• B. They may be released in the form of gases
• C. Electrolytic material may dissolve into the solution as ions
• D. In a Nelson cell, Na metal is a primary product

Explanation: The correct answer is D) In a Nelson cell, Na metal is a primary product. This statement is incorrect.

• A. NaCl(aq)
• B. NaCl(molten)
• C. NaCl(s)
• D. Silver metal

Explanation: The correct answer is C) NaCl(s). Solid sodium chloride does not conduct electricity because its ions are fixed in a lattice structure…

• A. Larger size of Li+
• B. Greater degree of hydration of Li+
• C. Larger radius to charge ratio of Li+
• D. Smaller nuclear charge of Li+

Explanation: The correct answer is B) Greater degree of hydration of Li+. Because Li+ ions are smaller, they attract more water molecules, leading to a…

• A. It involves conversion of electrical energy into chemical energy
• B. Anode has negative charge and cathode has positive charge in this cell
• C. It is reverse of addition reaction
• D. It is an endothermic process

Explanation: The correct answer is B) Anode has a negative charge, and cathode has a positive charge in this cell.

• A. Option A
• B. Option B
• C. Option C
• D. Option D

Explanation: The correct answer is Option A, the correct decreasing order of discharge of positive ions at the cathode based on the reactivity order of…

• A. A
• B. B
• C. C
• D. D

Explanation: The correct answer is A) Option A presents the correct decreasing order of discharge of negative ions on the anode electrode during the…

• A. Na reacts with water
• B. Na+ is more stable than Na atom
• C. Na+ reacts with Cl- ion in the solution
• D. Reduction of H2O is preferred to Na+

Explanation: During the electrolysis of an aqueous solution of NaCl, water is more easily reduced than Na+ ions, leading to the production of hydrogen…

• A. Extraction of sodium by the electrolysis of fused NaCI is carried in Down's cell
• B. Ca and Mg metals are extracted by the electrolysis of their fused chlorides
• C. It is used for the extraction of blistered copper from electrolytic copper
• D. Aluminium is extracted by electrolyzing fused bauxite (AI2O3 .2H2O) in the presence of fused cryolite (Na3AIF6)

Explanation: The correct answer is C) It is used for the extraction of blistered copper from electrolytic copper.

• A. H₂ + F₂ → 2HF
• B. H₂ + Cl₂ → 2HCl
• C. 2Na + H2 → 2NaH
• D. CuO + H₂ → Cu + H₂O

Explanation: An oxidizing agent is a substance that gets reduced (gains electrons). In the reaction with sodium, hydrogen goes from an oxidation state…

• A. Hydrogen
• B. Oxygen
• C. Steam
• D. Chlorine

Explanation: During the electrolysis of a dilute salt solution, water is decomposed.

• A. Negative reduction potential
• B. Negative oxidation potential
• C. Positive reduction potential
• D. Positive oxidation potential

Explanation: Coinage metals (Cu, Ag, and Au) are notable for their high positive reduction potentials.

• A. 9 electrons
• B. 6 electrons
• C. 3 electrons
• D. 2 electrons

Explanation: In an acidic medium Cr is reduced from +6 to +3 as:Cr2O7-2+ 14H+ +6e- → 2Cr+3 + 7H2Oand Fe2+ is oxidized to Fe3+ as:Fe2+→ Fe3++ e-So, 6…

• A. KMnO4
• B. K2Cr2O7
• C. H2SO4
• D. HI

Explanation: The correct answer is HI because it is a strong reducing agent, meaning it donates electrons to other substances rather than accepting…