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Q.
Graphite is soft while diamond is hard because:
BHUBHU 2003
Solution:
In diamond each carbon atom is $ sp^{3} $ hybridized and is joined to each by strong covalent bonds and form tetrahedral structure. In graphite carbon is $ sp^{2} $ hybridized. The carbon atoms join each other to form planar, hexagonal sheet like structure held together by weak van der Waal force. Therefore, diamond is harder than graphite.