MgCl2. XH2O, CaCl2.YH2O and BaCl2.Z H2O. The values of X, Y and Z are respectively

As the size of cation increases degree hydration decreases (or) extent of hydration decreases i.e., Number of water molecules associated in their respective salts decreasesMgCl2.XH2O   CaCl2.H2O   BaCl2.2H2OX=8           ,    y=6         & Z = 2→ MgCl2.8H2O  CaCl2.6H2O   BaCl2.2H2O