Question

Which of the following forms of silica is pseudo-isometric?

• A. Cristobalite
• B. Quartz
• C. Tridymite
• D. Coesite

Hint:

Cristobalite is a high-temperature silica polymorph and is commonly described as pseudo-isometric.

Answer 1

The Correct Option is A

Concept:
Silica \((SiO_2)\) occurs in different polymorphic forms such as quartz, tridymite, cristobalite and coesite.

Step 1: Understand pseudo-isometric form.
Pseudo-isometric means the crystal appears to have isometric or cubic symmetry, although its actual symmetry may be different.

Step 2: Identify the silica form.
Cristobalite is a high-temperature polymorph of silica and is commonly described as pseudo-isometric. \[ \text{Pseudo-isometric silica}=\text{Cristobalite} \]

Step 3: Final answer.
Therefore, the correct form is cristobalite. \[ \therefore \text{Correct Answer is (A)} \]