d and f BLOCK ELEMENTS

In the catalyzed reaction between iodide and persulphate ions, what is the overall effect of the iron catalyst?

• It is consumed and decreases the reaction rate
• It changes the products formed
• It is regenerated and increases the reaction rate
• It acts as a spectator ion

What is the main reason transition metal ions are effective catalysts in redox reactions?

• Their large ionic radii
• Their inability to form complexes
• Their fixed +2 oxidation state
• Their ability to easily change oxidation states

Which process uses nickel as a catalyst for the hydrogenation of unsaturated compounds?

• Contact Process
• Haber's Process
• Catalytic Hydrogenation
• Oxidation Process

What is the general effect of alloying pure metals like iron to form steels?

• It decreases hardness and melting point
• It has no effect on physical properties
• It often increases hardness and melting point
• It makes them more chemically reactive

Why are transition metals particularly prone to forming alloys with each other?

• They are all liquids at room temperature
• They have very low melting points
• They are highly reactive with oxygen
• Their similar atomic radii and other characteristics