Question

The solid element $A$ exhibits the property of catenation. It is also present in the form of a gas $B$ in the air which is utilized by plants in photosynthesis. An allotrope $C$ of this element is used in glass cutters.
(a) What is element $A$?
(b) What is the gas $B$?
(c) Name the allotrope $C$.
(d) State another use of allotrope $C$ (other than in glass cutters).
(e) Name another allotrope of an element $A$ which exists as spherical molecules.
(f) Name another allotrope of an element $A$ which conducts electricity.

Answer 1

(a) Carbon exhibits the property of catenation therefore element $A$ is carbon
(b) Carbon reacts with oxygen and forms carbon dioxide which is used by plants in photosynthesis. Therefore gas $B$ is carbon dioxide
(c) Allotrope of carbon which is used as glass cutters is diamond. So, allotrope $C$ is diamond
(d) Diamond is also used in making jewellery
(e) Another allotrope of carbon that exists as the spherical molecule is buckminsterfullerene.
(f) Graphite is the only allotrope of carbon that conducts electricity.