Which of the following is amorphous form of silica

Options

A. Quartz
B. Kieselguhr
C. Tridymite
D. Cristobalite

Answer

To determine which of the following is the amorphous form of silica, we need to understand the different forms that silica (SiO2) can take.

### Step-by-Step Solution:

1. **Identify Silica**: Silica is chemically represented as SiO2, consisting of one silicon atom and two oxygen atoms.

2. **Forms of Silica**: Silica can exist in various forms, primarily categorized into crystalline and amorphous forms.

3. **Crystalline Forms**: The crystalline forms of silica include:
- Quartz
- Tridymite
- Cristobalite
These forms have a well-defined geometric structure.

4. **Amorphous Forms**: In contrast, amorphous silica does not have a long-range order in its atomic arrangement. Common amorphous forms include:
- Onyx
- Kieselgut

5. **Select the Amorphous Form**: Among the options provided, we need to identify which one is an amorphous form. Based on the information:
- Kieselgut is recognized as an amorphous form of silica.

6. **Conclusion**: Therefore, the correct answer to the question is option B, Kieselgut.

### Final Answer:
**Option B: Kieselgut**

---