Multiple Choice QuestionsGraphite is a soft solid lubricant extremely difficult to melt. The reason for this anomalous behaviour is that, graphite
is a non-crystalline substance
is an allotropic form of diamond
has molecules of variable molecular masses like polymers
has carbon atoms arranged in large plates of rings of strongly bound carbon atoms with weak interplate bonds
D.
has carbon atoms arranged in large plates of rings of strongly bound carbon atoms with weak interplate bonds
C-atoms form covalently bonded plates layers. Layers are bonded weakly together, that's why one layer can slide over other cause lubricacy. It cannot be melted easily as large number of atoms being bonded strongly in the layer form big entity.
The structure of diborane (B2H6) contains
four 2C-2e- bonds and four 3C-2e- bonds
two 2C-2e- bonds and two 3C-3e- bonds
two 2C-2e- bonds and four 3C-2e- bonds
four 2C-2e- bonds and two 3C-2e- bonds
In silica (SiO2), each silicon atom is bonded to
two oxygen atoms
four oxygen atoms
one silicon and two oxygen atoms
one silicon and four oxygen atoms
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