Question

Which one of the following ores is known as Malachite ?
a.) $C{u_2}O$
b.) $C{u_2}S$
c.) $CuFe{S_2}$
d.) $Cu{(OH)_2} \cdot CuC{O_3}$

Answer 1

Hint: Malachite is the ore that contains copper carbonate hydroxide. Copper is obtained from this ore. The answer would contain copper in hydroxide and carbonate both forms. There is nothing to do with sulphur. It has molecular mass of 221.1 g /mol.

Complete step by step answer:
This type of question is very easy if we know the correct answer and can fetch us marks in seconds but if we do not know then it is a bit tough. But we can not attempt it then.
The Malachite is a mineral of copper. It is a copper carbonate hydroxide mineral. It has a molecular formula $Cu{(OH)_2} \cdot CuC{O_3}$.
So, the correct answer is “Option D”.

Additional Information:
It is opaque and green banded mineral crystal. It is in monoclinic form. Individual crystals are rare to find. But these can occur as slender to acicular prisms. It occurs due to weathering of copper ores and is found with azurite, goethite and calcite. It has many properties similar to azurite. It is associated with copper deposits around limestones which is a source of carbonate. One of the largest pieces of malachite is The Tazza ( a malachite vase), which is present in New York.

Note: This was used as a mineral pigment in green paints. This pigment is sensitive to acids and varies in colours. It has further use in very decorative things. There is a Malachite Room in the Hermitage museum that contains a malachite vase.