Question

Give a scientific reason why graphite is not used in ornaments.

Answer 1

Hint: The materials which are suitable for making ornaments are generally metals which are unreactive so that they do not get tarnish or oxidized in the presence of air. Moreover, the metals used in ornaments must be highly lustrous and highly malleable and ductile, so that it can be converted into any shape and design.

Complete answer:
We know that graphite is known as the most stable allotrope of carbon under standard conditions and is a good conductor of electricity with high melting point, which makes it suitable material for the electrodes required during electrolysis.
It is a mineral which is composed of layered sheets of carbon atoms having a hexagonal crystal structure. It is very soft, has high electrical and thermal conductivity, is relatively non-reactive and has a low specific gravity. Graphite is extremely soft so it breaks into thin flexible flakes easily which slide over one another and results in a greasy texture. Thus, graphite is considered as a good dry lubricant.
Although graphite is relatively non-reactive but it is not used in ornaments because of the following properties:
1. It is soft, brittle and slippery in nature because of the presence of weak van der Waal forces existing between the sheets of carbon atoms.
2. It is non ductile i.e., it cannot unlike gold and silver, it cannot be moulded into different designs and shapes.

Note:
Remember that relatively less reactive metals like platinum, gold and silver are used for making ornaments or jewellery because these metals are highly lustrous which are resistant to corrosion and are highly malleable and ductile. Moreover, in the presence of oxygen these metals do not tarnish readily.