Q. Which of the following is/are correct for allotropes of carbon?

1. They are two in number.
2. In diamond, each carbon atom is bonded to four other carbon atoms.
3. In graphite, each carbon atom is bonded to three other carbon atoms in the same plane giving a hexagonal array.

Select the correct answer from the codes given below:
Answer: Only 2 and 3
Notes: The element carbon occurs in different forms in nature with widely varying physical properties. Both diamond and graphite are formed by carbon atoms, the difference lies in the manner in which the carbon atoms are bonded to one another. In diamond, each carbon atom is bonded to four other carbon atoms forming a rigid three-dimensional structure. In graphite, each carbon atom is bonded to three other carbon atoms in the same plane giving a hexagonal array. Fullerenes form another class of carbon allotropes. The first one to be identified was C-60 which has carbon atoms arranged in the shape of a football.