Zeolites are used as catalyst in :

Options

A. Petrochemical industries during cracking
B. In the preparation of `H_(2)SO_(4)`
C. In the hydrolysis of ester
D. All

Answer

**Step-by-Step Solution:**

1. **Understanding Zeolites**: Zeolites are a class of minerals that have a unique crystalline structure with a network of pores and channels. This structure allows them to act as shape-selective catalysts.

2. **Identifying the Role of Zeolites**: The primary role of zeolites in catalysis is due to their ability to selectively allow certain molecules to enter their pores while excluding others. This property makes them highly effective in various catalytic processes.

3. **Application in Petrochemical Industry**: Zeolites are predominantly used in the petrochemical industry. One of the key processes where zeolites serve as catalysts is during the cracking of hydrocarbons. Cracking is a method used to break down larger hydrocarbon molecules into smaller, more useful ones.

4. **Example of a Zeolite Catalyst**: A specific example of a zeolite used in the petrochemical industry is ZSM-5. This zeolite is known for its effectiveness in catalytic cracking processes.

5. **Exclusion of Other Processes**: It is important to note that zeolites are not typically used in processes such as the preparation of sulfuric acid (H2SO4) or in the hydrolysis of esters. Their primary application remains in the petrochemical sector.

6. **Conclusion**: Based on the above points, the correct answer to the question is that zeolites are used as catalysts in the petrochemical industry, specifically during the cracking process.

**Final Answer**: Zeolites are used as catalysts in the petrochemical industry during cracking.

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