Question

Which one of the following isotope of carbon is thermodynamically more stable ?

• A. Buckminsterfullerene
• B. Graphite
• C. Diamond
• D. None of the above

Answer 1

The correct option is B Graphite

Graphite is thermodynamically most stable allotrope of carbon, hence $\Delta H_f^o$ of graphite is taken as zero.
$\Delta H_f^o$ of diamond = 1.90$kJmo{l}^{-1}$
$\Delta H_f^o$ of Fullerene $C_{60}$=38.1 $kJmo{l}^{-1}$