Question

Which of the following is an ore of mercury?
(A) Bauxite
(B) Haematite
(C) Cinnabar
(D) Dolomite

Answer 1

Hint: Bauxite and haematite are oxide ores, cinnabar is a sulphide ore and dolomite is a carbonate ore. If we remember the metal in all these ores, we can identify the ore of mercury.

Complete step by step answer:
(A) Bauxite is an ore of aluminium with the composition of \[{\text{A}}{{\text{l}}_{\text{2}}}{{\text{O}}_{\text{3}}} \cdot x{{\text{H}}_{\text{2}}}{\text{O}}\].
(B) Haematite is an ore of iron with the composition of \[{\text{F}}{{\text{e}}_{\text{2}}}{{\text{O}}_{\text{3}}}\].
(D) Dolomite is an ore of magnesium and calcium with the composition of \[{\text{MgC}}{{\text{O}}_{\text{3}}} \cdot {\text{CaC}}{{\text{O}}_3}\].
(C) Cinnabar is an ore of mercury with the composition of \[{\text{HgS}}\].
Hence, the correct option is C.

Note: Minerals are naturally occurring substances in the earth’s crust obtained by mining. For a particular metal, there may be many minerals from which metal can be extracted. Out of these minerals only a few are financially viable to be used as sources of that metal. These minerals are known as ores.
Most of the mercury is obtained from cinnabar or vermillion. It is usually found in granular form or small crystals. It is bright red in colour.
Extraction of mercury from cinnabar ore-
Cinnabar is heated in a current of air.
\[{\text{HgS (s)}} + {{\text{O}}_{\text{2}}}{\text{ (g)}}\xrightarrow{\Delta }{\text{Hg (g)}} + {\text{S}}{{\text{O}}_{\text{2}}}{\text{ (g)}}\]
Due to its low boiling point, the formed mercury vapour is condensed. The collected mercury can be easily purified by vacuum distillation.
We should remember important ores for a few of the metals. Generally, important ores are oxides, sulphides, carbonates, sulphates or halides.