68th B.P.S.C. (Pre) 2022
Which of the following statements about diamond and graphite is true?
aThey have same electrical conductivity
bThey have same crystal structure
cThey have same degree of hardness
dMore than one of the above
eNone of the above✓ Correct
Explanation
Diamond and graphite are both known as allotropes of carbon, but neither their crystal structure nor their hardness is the same. In diamond, carbon atoms form a three-dimensional tetrahedral structure, whereas in graphite they form planar hexagonal rings. Diamond is the hardest substance, while graphite is very soft. Similarly, diamond is a poor conductor of electricity, whereas graphite is an excellent conductor. Hence, option (e) is the correct answer.
general-science