Question

Which one of the following is an ore of potassium?

• A. Cryolite
• B. Carnallite
• C. Bauxite
• D. Dolomite

Hint:

Carnallite (KCl\(\cdot\)MgCl\(_2\cdot\)6H\(_2\)O) and Sylvite (KCl) are the primary minerals processed to manufacture Muriate of Potash (MOP), which is the most widely used potassium fertilizer in agriculture.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Potassium (K) is a highly reactive alkali metal and is not found as a free element in nature.
It is extracted from evaporite mineral deposits that contain potassium salts.

Step 2: Detailed Explanation:
Let us review the chemical composition of each mineral listed in the options:
- Option (A) Cryolite: Formulated as Na\(_3\)AlF\(_6\). It is a rare halide mineral used in the industrial metallurgy of aluminum. It does not contain potassium.
- Option (B) Carnallite: Formulated as KCl\(\cdot\)MgCl\(_2\cdot\)6H\(_2\)O. It is a double-salt hydrated chloride mineral containing both potassium and magnesium. It serves as a primary source for potassium fertilizer production (potash).
- Option (C) Bauxite: An aluminum-rich sedimentary rock that serves as the principal ore of aluminum. It contains no potassium.
- Option (D) Dolomite: Formulated as CaMg(CO\(_3\))\(_2\). It is an anhydrous carbonate mineral composed of calcium magnesium carbonate, containing no potassium.
Thus, Carnallite is the only potassium-bearing ore among the options.

Step 3: Final Answer:
The correct option is (B).