Metals as we know are very useful in all fields , industries in particular. Non - Metals are no less in any way . Oxygen present in air is essential for breathing as well as for combustion . Non metals form a large number of compounds which are extremely useful, eg, ammonia, nitric acid, sulphuric acid , etc. Non- metals are found to exist in three states of matter. Only solid non-metals are expected to be hard however they have low density and are brittle . They usually have low melting and boiling point and are poor conductors of electricity.Generally , non metals are bad conductors of electricity but 'X' which is a form of carbon is a good conductor of electricity and is an exceptional non-metal. 'X' is

Options

A. Diamond
B. Graphite
C. Coal
D. Coke

Answer

B