Question

Malachite is a mineral of metal ‘X’. Its composition is: 
 

• A. \({Al}_2{O}_3 \cdot 2{SiO}_2 \cdot 2{H}_2{O}\)
• B. \({CuCO}_3 \cdot {Cu(OH)}_2\)
• C. \({CuCO}_3 \cdot {Cu}_2{S}\)
• D. \({CaSO}_4 \cdot 2{H}_2{O}\)

Hint:

Malachite is an important copper ore, distinguished by its green color and association with other secondary copper minerals like Azurite (\({Cu}_3({CO}_3)_2({OH})_2\)).

Answer 1

The Correct Option is B

Malachite is a basic copper carbonate mineral with the chemical formula:
\[ {CuCO}_3 \cdot {Cu(OH)}_2 \]
It is one of the most important ores of copper and is often found in green crystalline or massive forms in copper deposits.
- Option 1 (\({Al}_2{O}_3 \cdot 2{SiO}_2 \cdot 2{H}_2{O}\)) represents Kaolinite, a clay mineral.
- Option 3 (\({CuCO}_3 \cdot {Cu}_2{S}\)) is incorrect as Malachite does not contain sulfide (\({S}^{2-}\)).
- Option 4 (\({CaSO}_4 \cdot 2{H}_2{O}\)) represents Gypsum, a sulfate mineral.
Thus, the correct formula for Malachite is \( {CuCO}_3 \cdot {Cu(OH)}_2 \).