\[{{C}_{\text{(graphite)}}}+{{O}_{2}}(g)\,\to \,C{{O}_{2}}(g)\] \[\Delta H=-94.05\,kcal\,mo{{l}^{-1}}\] \[{{C}_{\text{(diamond)}}}+{{O}_{2}}(g)\,\to \,C{{O}_{2}}(g);\,\]\[\Delta H=-94.50\,kcal\,mo{{l}^{-1}}\] therefore [DPMT 2001]

Diamond is harder than graphite

\[{{C}_{\text{(graphite)}}}\,\to \,{{C}_{\text{(diamond)}}}\]; \[\Delta H_{298K}^{o}=-450\,cal\,mo{{l}^{-1}}\]

\[{{C}_{\text{(diamond)}}}\,\to \,{{C}_{\text{(graphite)}}};\] \[\Delta H_{298K}^{o}=+450\,cal\,mo{{l}^{-1}}\]

Graphite is the stabler allotrope

\[{{C}_{\text{(graphite)}}}+{{O}_{2}}(g)\,\to \,C{{O}_{2}}(g)\]

1.	\[{{C}_{\text{(graphite)}}}+{{O}_{2}}(g)\,\to \,C{{O}_{2}}(g)\] \[\Delta H=-94.05\,kcal\,mo{{l}^{-1}}\] \[{{C}_{\text{(diamond)}}}+{{O}_{2}}(g)\,\to \,C{{O}_{2}}(g);\,\]\[\Delta H=-94.50\,kcal\,mo{{l}^{-1}}\] therefore [DPMT 2001]
A.	\[{{C}_{\text{(graphite)}}}\,\to \,{{C}_{\text{(diamond)}}}\]; \[\Delta H_{298K}^{o}=-450\,cal\,mo{{l}^{-1}}\]
B.	\[{{C}_{\text{(diamond)}}}\,\to \,{{C}_{\text{(graphite)}}};\] \[\Delta H_{298K}^{o}=+450\,cal\,mo{{l}^{-1}}\]
C.	Graphite is the stabler allotrope
D.	Diamond is harder than graphite
Answer» D. Diamond is harder than graphite

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\[{{C}_{\text{(graphite)}}}+{{O}_{2}}(g)\,\to \,C{{O}_{2}}(g)\] \[\Delta H=-94.05\,kcal\,mo{{l}^{-1}}\] \[{{C}_{\text{(diamond)}}}+{{O}_{2}}(g)\,\to \,C{{O}_{2}}(g);\,\]\[\Delta H=-94.50\,kcal\,mo{{l}^{-1}}\] therefore [DPMT 2001]

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