d and f BLOCK ELEMENTS

What is the main reason for the difference in color between MnO₄⁻ (purple) and MnO₄²⁻ (green)?

• Different oxidation states lead to different electronic transitions
• Different numbers of oxygen atoms
• Different overall charges
• Different molecular geometries

What is the main product formed at the cathode during the electrolysis of an aqueous solution containing Mn²⁺ ions?

• Manganese metal
• Oxygen gas
• Hydrogen gas
• Permanganate ions

What is the main product formed at the anode during the electrolysis of an aqueous solution containing Mn²⁺ ions using inert electrodes?

• Oxygen gas
• Manganese metal
• Hydrogen gas
• Permanganate ions

What happens to the oxidation state of manganese in the half-reaction MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O?

• It decreases from +7 to +2
• It increases from +2 to +7
• It stays the same
• It becomes zero

How many oxygen atoms are directly bonded to the central manganese atom in the permanganate ion?

• 4
• 3
• 2
• 1