Question

In graphite , carbon atoms are joined together due to :
A.Ionic bonding
B.Van der waals forces
C.Metallic bonding
D.Covalent bonding

Answer 1

Hint: Graphite is an allotrope of carbon . Allotropes are different structural modifications of an element , which have different physical properties but identical chemical properties.

Complete step by step answer:
Graphite is a naturally occuring allotrope of carbon and it can also be manufactured artificially .
In graphite the carbon atoms are $s{p^2}$ - hybridised . Each carbon atom is linked to three other carbon atoms forming hexagonal rings . Thus , graphite has a two - dimensional sheet like layered structure consisting of benzene rings fused together . The successive layers in graphite are held together by weak van der Waals forces of attraction and so one layer can slip over the other which makes it soft . The distance between any two successive layers is $3.40{A^ \circ }$ .
The carbon atoms in graphite are covalently bonded and the $C - C$ bond length in graphite is $1.415{A^ \circ }$ because of $s{p^2}$ hybridisation .
Hence , carbon atoms are held by covalent bonding and option D is correct .

Additional Information:
Unlike diamond , graphite is soft and a good lubricating agent .
Since only three electrons of each carbon are used in making hexagonal rings in graphite , the fourth valence electron of each carbon is free to move , which makes graphite a good conductor of heat and electricity .

Note:
Among all the allotropes of carbon , graphite is thermodynamically the most stable allotrope . Its standard enthalpy of formation is taken as zero $({\Delta _f}H = 0)$ , whereas the standard enthalpy of formation of other allotropes is not zero . The enthalpy of formation of diamond and fullerene are $1.98$ and $38.1kJmo{l^{ - 1}}$ respectively .