Identify the correct formula of halides of alkaline earth metals from the following.

1.  BaCl2·2H2O

2.  BaCl2·4H2O

3.  CaCl2·6H2O

4.  SrCl2·4H2O

Choose the correct option
1. (a, b)
2. (b, c)
3. (c, d)
4. (a, c)



Hint: Hydration energy decreases down the group
All the chlorides of alkaline earth metals are hydrated to different extents and the extent of hydration decreases from Mg to Ba e.g. MgCl2·6H2OCaCl2·6H2OBaCl2·2H2OSrCl2·2H2O.