Question

Arrange the following steps of sol-gel method in correct order:
A. Gelation,
B. Hydrolysis,
C. Sintering,
D. Drying.

• A. B, A, D, C
• B. B, A, C, D
• C. A, B, C, D
• D. D, A, C, B

Hint:

Sol-gel sequence is hydrolysis, gelation, drying and sintering.

Answer 1

The Correct Option is A

Concept:
Sol-gel method is a bottom-up technique used to synthesize materials from molecular precursors.

Step 1: Hydrolysis.
The process begins with hydrolysis of precursor molecules. \[ \text{First step}=B \]

Step 2: Gelation.
After hydrolysis and condensation reactions, a gel network is formed. \[ \text{Second step}=A \]

Step 3: Drying.
The gel is dried to remove solvent and obtain xerogel or dried gel. \[ \text{Third step}=D \]

Step 4: Sintering.
Finally, sintering or heat treatment is done to improve density and crystallinity. \[ \text{Fourth step}=C \] Therefore, the correct sequence is: \[ B,A,D,C \] \[ \therefore \text{Correct Answer is (A)} \]