Question
Question: A chloride dissolves appreciably in cold water. When placed on a platinum wire in Bunsen flame, no d...
A chloride dissolves appreciably in cold water. When placed on a platinum wire in Bunsen flame, no distinctive colour is noticed. The cation of chloride is
A
Mg2+
B
Ba2+
C
Pb2+
D
Ca2+
Answer
Mg2+
Explanation
Solution
MgCl2, BaCl2 and CaCl2 appreciably dissolve in cold water because their hydration energies exceed the lattice energies. Ba2+ and Ca2+ impart apple green and brick red colour to the flame respectively.
The electrons in magnesium are too strongly bound to get excited by flame. Hence this element does not impart any colour to the flame.
Note : PbCl2 does not impart any colour to the flame but it is insoluble in cold water