Which of the following are the example of double salt?
A $FeSO _4 \left( NH _4\right)_2 SO _4 \cdot 6 H _2 O$
B $CuSO _4 4 NH _3 H _2 O$
C $K _2 SO _4 \cdot Al _2\left( SO _4\right)_3 \cdot 24 H _2 O$
D $Fe ( CN )_2 \cdot 4 KCN$
Choose the correct answer
A $FeSO _4 \left( NH _4\right)_2 SO _4 \cdot 6 H _2 O$
B $CuSO _4 4 NH _3 H _2 O$
C $K _2 SO _4 \cdot Al _2\left( SO _4\right)_3 \cdot 24 H _2 O$
D $Fe ( CN )_2 \cdot 4 KCN$
Choose the correct answer
Show Hint
Double salts completely dissociate into their constituent ions in water, while co ordination compounds do not dissociate fully due to the formation of coordina tion complexes.
- A and B only
- A, B and D only
- A and C only
- B and D only
The Correct Option is C
Solution and Explanation
Analysis of Double Salts and Coordination Compounds:
Double salts are compounds that dissociate completely into their constituent ions when dissolved in water. They are formed by the combination of two salts and retain their identity only in the crystalline state. The analysis of the given options is as follows:
- (A) FeSO4 · (NH4)2SO4 · 6H2O: Known as Mohr’s salt, this is a classic example of a double salt.
- (B) CuSO4 · 4NH3 · H2O: This is a coordination compound, not a double salt.
- (C) K2SO4 · Al2(SO4)3 · 24H2O: Known as potash alum, this is a double salt.
- (D) Fe(CN)2 · 4KCN: This is a coordination compound (ferrocyanide complex), not a double salt.
Conclusion: The correct examples of double salts are (A) and (C).
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Concepts Used:
Coordination Compounds
A coordination compound holds a central metal atom or ion surrounded by various oppositely charged ions or neutral molecules. These molecules or ions are re-bonded to the metal atom or ion by a coordinate bond.
Coordination entity:
A coordination entity composes of a central metal atom or ion bonded to a fixed number of ions or molecules.
Ligands:
A molecule, ion, or group which is bonded to the metal atom or ion in a complex or coordination compound by a coordinate bond is commonly called a ligand. It may be either neutral, positively, or negatively charged.