IIT-JEE 2012 · Paper 2 · Chemistry Q38

ChemistryMultiple correct+4Question 38 of 60

With respect to graphite and diamond, which of the statement(s) given below is (are) correct?

Graphite is harder than diamond.

Graphite has higher electrical conductivity than diamond.

Graphite has higher thermal conductivity than diamond.

Graphite has higher C-C bond order than diamond.

Answer and worked solution

Official answer: B, D

(A) Diamond (a 3D network of $sp^3$ C-C bonds) is the hardest natural substance; graphite's layers slide over each other. False.
(B) Graphite's delocalised π electrons conduct within the layers; diamond is an insulator. True.
(C) Diamond has a very high thermal conductivity (carried by lattice vibrations of its stiff network), higher than graphite's. False.
(D) In graphite each C-C bond has bond order about $1\frac13$ (one π bond shared over three bonds); in diamond it is 1. True.

(B), (D)

Topics:Group 14 Bond parameters and dipole moment

IIT-JEE 2012 · Paper 2, Chemistry question 38