d and f BLOCK ELEMENTS

What general reaction do lanthanoids undergo with dilute acids?

• They form water
• They liberate hydrogen gas
• They absorb the acid
• They become passive

For which application are mixed oxides of lanthanoids commonly used?

• Permanent magnets
• Catalysts in petroleum cracking
• High-temperature superconductors
• Nuclear reactor moderators

What is Mischmetall primarily composed of?

• 100% pure lanthanum
• ~50% lanthanoid metal and ~50% iron
• ~95% lanthanoid metal and ~5% iron
• ~95% iron and ~5% lanthanoid metal

What is a major industrial application of lanthanoids?

• Catalysts in plastic production
• Production of alloy steels
• Semiconductor manufacturing
• Nuclear fuel rods

What type of compounds are formed when lanthanoid metals are heated with carbon?

• Oxides
• Carbides
• Sulfides
• Halides