Question
Which one is a double salt?
- Ca(OCl)Cl (bleaching powder)
- NaKCO3
- [Cu(NH3)4]SO4
- FeSO4.(NH4)2SO4-6H2O (Mohr’s salt)
Answer
FeSO4.(NH4)2SO4.6H2O (Mohr’s salt)
Explanation
FeSO4.(NH4)2SO4.6H2O (Mohr’s salt) is a double salt that forms a blue-green crystalline compound. NaKCO3 is a mixture of two different salts, while Ca(OCl)Cl (bleaching powder) and [Cu(NH3)4]SO4 are not double salts.