The formula of carnallite is:

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$KCl \cdot M_{5} {Cl}_{2} \cdot 6 H_{2} O$

$K_{2} O \cdot {Al}_{2} O_{3} \cdot 6 {SiO}_{2}$

$KCl \cdot {MgCl}_{2} \cdot 2 H_{2} O$

$LiAl {({Si}_{2} O_{5})}_{2}$

answer is B.

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Detailed Solution

Carnallite, also known as potassium magnesium chloride, is a hydrated evaporite mineral with the chemical formula: KMgCl₃ ⋅ 6H₂O.

It consists of:

Properties of Carnallite:

Appearance: Carnallite can appear in various colors, including yellow, white, reddish, colorless, or even blue.
Nature: It is a naturally occurring evaporite mineral that forms in arid environments where seawater has evaporated.

Explanation of the Correct Answer:

The carnallite formula shows the combination of potassium, magnesium, chloride ions, and water molecules in a specific hydrated structure.

- The presence of water of crystallization makes it a hydrated salt.

- This unique composition is why carnallite is used as a source for magnesium and potassium in industrial applications.

Correct Option: (b) KCl ⋅ MgCl₂ ⋅ 6H₂O

Why This Answer Is Correct?

- The chemical formula KCl ⋅ MgCl₂ ⋅ 6H₂O represents the exact structure of carnallite.

- Other options do not include both magnesium chloride and water molecules, which are essential parts of the carnallite formula.

Key Takeaways

Carnallite Formula: KCl ⋅ MgCl₂ ⋅ 6H₂O
Composition: Contains potassium chloride, magnesium chloride, and water molecules.
Uses: It is a source of magnesium and potassium, commonly found in evaporite deposits.

The correct answer is option b because it accurately represents the composition of carnallite.

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