Problem 32 - A Complete Resource Book in Chemistry for JEE Main

Question

The ore which contains copper and iron both is (a) cuprite (b) chalcocite (c) chalcopyrite (d) malachite

Step-by-Step Solution

Answer

The ore containing both copper and iron is chalcopyrite.

Step 1: Understanding the Question

We need to determine which ore contains both copper and iron. The question provides us with four options: cuprite, chalcocite, chalcopyrite, and malachite. Each of these are known ores with typical compositions.

Step 2: Examining the Options

To solve this problem, let's analyze the composition of each given ore: - Cuprite (Cu extsubscript{2}O): Contains only copper and oxygen. - Chalcocite (Cu extsubscript{2}S): Contains only copper and sulfur. - Chalcopyrite (CuFeS extsubscript{2}): Contains copper, iron, and sulfur. - Malachite (Cu extsubscript{2}(CO extsubscript{3})(OH) extsubscript{2}): Contains copper, carbon, oxygen, and hydrogen.

Step 3: Identifying the Ore with Both Copper and Iron

Review the compositions analyzed in the previous step to identify the ore containing both copper and iron. Chalcopyrite, with the formula CuFeS extsubscript{2}, includes copper (Cu) and iron (Fe) along with sulfur (S). This confirms that chalcopyrite is the ore we are looking for.

Key Concepts

Chalcopyrite

Chalcopyrite is a prominent mineral used for extracting copper. This mineral is a sulfide ore, characterized by its brassy yellow color due to its unique combination of elements. The chemical formula for chalcopyrite is \( \text{CuFeS}_{2} \), which signifies the presence of copper (Cu), iron (Fe), and sulfur (S).
It often forms under sedimentary and volcanic environments. Chalcopyrite is frequently located in veins and disseminations within igneous rocks. The mix of copper and iron makes it crucial in industrial processes. A simple way to remember chalcopyrite is as the primary source of copper, an element essential for electrical wiring and corrosion-resistant alloys.

Chemical Composition of Ores

Understanding the chemical composition of ores is essential in identifying the presence of specific metals in a compound. Ores are naturally occurring solids made up of minerals.
List of elements typically includes:

• Metals: The valuable component extracted, like copper in chalcopyrite.
• Non-metals: Elements that often mix with metals, such as sulfur.
• Compounds: Structures forming the ores, where metals are bonded with other elements.

For example, in chalcopyrite, copper and iron are bonded with sulfur, forming the compound \( \text{CuFeS}_{2} \). Understanding this helps in pinpointing the correct extraction process, as different elements and their bonds require varied methods for separation.

Metal Extraction

Metal extraction involves separating the desired metal from its ore. Each process varies depending on the ore's chemical composition and the metal's reactivity. Here’s a general overview of the main steps involved:

• Crushing and Grinding: The ore is first broken down physically.
• Concentration: Techniques like flotation concentrate the metal-rich mineral.
• Extraction: Chemical reactions like roasting and smelting release the metal. For chalcopyrite, methods such as hydrometallurgy and pyrometallurgy are used.
• Refining: Further purification, often through electrolysis.

In cases such as chalcopyrite, extracting copper involves heating to separate sulfur and iron sulfide, leaving behind pure copper. Each step needs careful control to optimize the yield of copper, ensuring the process is economically viable and environmentally safe.