International General Certificate of Secondary Education (IGCSE) Chemistry Practice Exam

What kind of catalyst is commonly used in the cracking process?

1. Gold catalyst

2. Nichrome catalyst

3. Aluminium oxide catalyst

4. Iron catalyst

The correct answer is: Aluminium oxide catalyst

The cracking process, which involves breaking down larger hydrocarbon molecules into smaller ones to produce alkenes and alkanes, commonly utilizes an aluminium oxide catalyst. This catalyst is effective due to its ability to provide the necessary surface area and support for the reactions to occur. Aluminium oxide can facilitate the breaking of carbon-carbon bonds and enables the rearrangement of hydrocarbon structures, making it a suitable choice for this process. Other catalysts like iron, gold, or nichrome are not typically employed in the cracking process. Iron is more relevant in processes like the Haber process for ammonia synthesis, while gold is often used in specific oxidation reactions, and nichrome is primarily utilized as a heating element due to its high resistance rather than in catalytic cracking. Thus, aluminium oxide's properties and role in catalyzing the cracking reactions make it the preferred catalyst in this chemical process.