Question

The common thing between graphite and diamond is that both have:
A.equal density
B.crystalline structure
C.high refractive index
D.high electrical conductivity

Answer 1

Hint: Carbon has two allotropes. These two allotropes are diamond and graphite. The carbon atoms in the structure are bound by covalent bonds.

Complete step by step solution:
We know that the carbon atom in both the diamond and in the graphite are arranged regularly to make a crystal. The common thing in graphite and diamond hence their crystalline crystal structure.
Therefore, out of the given four options, B is the correct option. A, C and D are incorrect options.

Hence, the correct answer is option B.

Additional information:
All the carbon atoms of Diamond are connected by strong chemical bonds with the other four carbon atoms, making a perfect tetrahedron structure. The carbon atoms in diamond are all \[{\text{s}}{{\text{p}}^{\text{3}}}\] hybridized. The bond lengths of carbon-carbon atoms in diamond are equal. Diamond forms a three-dimensional network of strong covalent bonds.
Diamond is the hardest substance on the Earth. It is used in making tools used for grinding, drilling, cutting, etc. Diamond is also used in the making of filaments which are made of tungsten used in the light bulbs. It is also used in the making of jewellery.
In Graphite all the carbon atoms have stable chemical bonds with that of the three other carbon atoms and make a sheet. The sheet are held by the weak form of forces.The carbon atoms in the Graphite structure are all \[{\text{s}}{{\text{p}}^2}\] hybridized and it forms hexagonal rings. The rings are composed of many layers of particles. Graphite powder is used as lubricants in the form of powder.
Graphite is used in lead pencils. It is used for the manufacture of the carbon electrodes which are used in the electrolytic cells. It is also used in the moderators and nuclear reactors.

Note: Diamond has a very high melting point of about \[{\text{3843}}\,\,{\text{K}}\] and a high density of about \[3.51\,{\text{g/c}}{{\text{m}}^{\text{3}}}\]. It is a poor conductor of electricity. Graphite has a low electrical conductivity with a low density of about \[2.26\,{\text{g/c}}{{\text{m}}^{\text{3}}}\].