Question

The diatomaceous earth is used to insulate boilers and steam pipes because

• A. The wall of diatoms is deposited with calcium.
• B. The diatomaceous earth is cheap.
• C. It is a good conductor of heat.
• D. The wall of diatoms is made of silica.

Answer 1

The correct option is D The wall of diatoms is made of silica.

Cells of diatoms are surrounded by the cell wall, deposited with silica called as frustules which are composed of two overlapping halves (the epitheca and the hypotheca). Shells of diatoms are highly resistant to decomposition due to the presence of silica and are deposited in ocean beds leading to the formation of the diatomaceous earth. This is used as filters because its silica content makes it chemically inactive and uncompressible during insulation. Thus, the correct answer is option D.