d and f BLOCK ELEMENTS

According to the text, what condition favors the formation of chromate ions (CrO4^2-) in aqueous solution?

• Acidic conditions (low pH)
• Basic conditions (high pH)
• Neutral conditions only
• Temperature changes

What is the main difference in the structures of chromate (CrO4^2-) and dichromate (Cr2O7^2-) ions as described?

• Chromate is linear, dichromate is tetrahedral
• Chromate is tetrahedral, dichromate consists of two tetrahedra sharing a corner
• Both are tetrahedral
• Chromate consists of two tetrahedra, dichromate is tetrahedral

In the preparation of KMnO4, what is the purpose of the electrolytic oxidation step?

• To reduce permanganate to manganate
• To convert manganate (MnO4^2-) to permanganate (MnO4^-)
• To precipitate MnO2
• To neutralize the solution

What is the significance of the standard electrode potential (E° = 1.33 V) for the dichromate reduction half-reaction?

• It indicates the reaction is slow
• It indicates a strong tendency for the reduction to occur spontaneously
• It shows the reaction requires energy input
• It is only relevant at high temperatures

Why is the dichromate ion (Cr2O7^2-) considered a strong oxidizing agent?

• Because it contains oxygen
• Because it is brightly colored
• Because chromium is in a high oxidation state (+6) which is readily reduced
• Because it is a large ion