d and f BLOCK ELEMENTS

Which method is described for the commercial preparation of potassium permanganate?

• Heating MnO2 with KOH
• Direct electrolysis of MnO2
• Alkaline oxidative fusion of MnO2 followed by electrolytic oxidation
• Reduction of MnO2 with hydrogen

According to the provided text, what happens to sulphide ions when they react with acidified potassium dichromate?

• They are reduced to hydrogen sulphide
• They precipitate as chromium sulphide
• They are oxidized to sulphur
• They remain unchanged

What is the final ionic product containing chromium when acidified potassium dichromate acts as an oxidizing agent?

• Cr^6+
• Cr^3+
• Cr2O7^2-
• CrO4^2-

Which of the following is NOT listed as a substance oxidized by acidified potassium dichromate in the text?

• Iodides
• Sulphides
• Tin(II) salts
• Manganese(II) salts

What is one of the products formed when acidified potassium dichromate reacts with iron(II) salts?

• Iron(II) salts
• Oxygen gas
• Iron(III) salts
• Hydrogen gas