Question

Which statement about diamond and graphite is correct?
A Diamond and graphite have low melting points.
B Diamond and graphite have mobile electrons.
C Diamond and graphite have layered structures.
D Diamond and graphite contain strong covalent bonds between carbon atoms.

Answer 1

Answer:

the correct option is d

becoz they react with atoms of carbon

and contain strong covalent

Answer 2

Answer:

$\sf\red{➢Answer}$

D. Diamond and graphite contain strong covalent bonds between carbon atoms.

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$\sf\red{➢Complete \: Answer}$

Both diamond and graphite are covalent network solids.

Let us look into their properties one by one.

In diamond, each carbon forms four covalent bonds with other carbon atoms in a three dimensional structure and these bonds are very strong. Due to the very strong covalent bonds, the melting point of diamond is very high since melting requires the breaking of the lattice structure which in turn leads to the breaking of the covalent bonds. Due to the same reason diamond is very hard. Diamond is an insulator i.e. it does not conduct electricity due to the lack of free electrons. It is also not soluble in water or any organic solvent because of its very high lattice enthalpy which cannot be overcome by its solvation enthalpy.

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$\sf\red{➢Reason}$

The bonds existing between the carbon atoms in a particular layer are stronger than the bonds in diamond because of the presence of free electrons in graphite that provides additional bonding. Like diamond, graphite has a high melting point and is insoluble in water or organic solvents. Due to the presence of delocalised electrons, graphite conducts electricity.

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❏Hence, the correct answer to the above question is (d) Diamond and graphite contain strong covalent bonds between carbon atoms.