d and f BLOCK ELEMENTS

What is the first step in the industrial preparation of dichromates from chromite ore?

• Heating chromite ore alone to high temperatures
• Electrolyzing a solution of chromite
• Fusing chromite ore with sodium or potassium carbonate in the presence of air
• Reacting chromite ore directly with sulfuric acid

What is the main industrial application of K2Cr2O7 mentioned in the text?

• As a reducing agent in metallurgy
• As a catalyst in polymerization
• As an oxidant for preparation of azo compounds
• As a dehydrating agent in organic synthesis

What is the primary reason Mn2O7 is described as a "covalent green oil"?

• It is a liquid at room temperature due to weak van der Waals forces
• It readily dissolves in oils
• Its high oxidation state leads to significant covalent bonding and low melting point
• It contains organic groups that make it oily

Why are higher oxidation state transition metal oxides generally more acidic than lower oxidation state oxides?

• Higher oxidation states are inherently more stable
• Higher oxidation states have greater charge density, polarizing oxide anions and favoring covalent bonding
• Higher oxidation states make the oxide more ionic
• Higher oxidation states decrease the electronegativity of the metal

Which transition metal oxide marks the end of the trend where the highest oxidation number coincides with the group number?

• Fe2O3
• CrO3
• Mn2O7
• V2O5