Question

A. Graphite acts as lubricant due to layer like structure.
B. The distance between two layers in graphite is ${1.42}^{\circ }A$.
C. Silica does not react with HCl, HBr and Hl.
Which of the above statement(s) is/are true?

• A. A & C
• B. A & B
• C. only 'A'
• D. A, B & C

Answer 1

The correct option is A A & C

A) Graphite has layer structure. Each layer is a planar sheet, composed of hexagonal rings of carbon atoms, with 3 electrons of each atom involved in strong single bonds with three adjacent atoms of hexagonal ring. The extra electron makes a very weak bond with the adjacent layer. Thus, one layer can slide over another and thus, it can be used as a lubricant.
B) The interlayer spacing is 3.35${}^0$A, and not 1.42${}^0$A. Since the layers are not joined by single bonds and 1.42${}^0$A is the distance between two carbon atoms joined by single bond.
C) Silica is an acidic oxide and reacts only with bases and not with the acids like above.