`CaCl_(2).2H_(2)O` में Ca, Cl एव `H_(2)O` का प्रतिशत संघटन ज्ञात कीजिए.

Ca + H_(2) O to

CaCO_(3) + ………to CaCl_(2) + H_(2)O + ……………

Ca+H_2O to

MgCl_(2).XH_(2)O, CaCl_(2).YH_(2)O and BaCl_(2).Z H_(2)O . The values of X, Y and Z are respectively

Halides of alkaline earth metals form hydrates such as MgCl_(2).6H_(2)O,CaCl_(2).6 H_(2)O,BaCl_(2).2H_(2)O and SrCl_(2).2H_(2)O . This shows that halides of group 2 elements :

Given CaCl_(2)(s) +aq rarr CaCl_(2)(aq): DeltaH^(Theta) = 75 kJ mol^(-1) at 18^(@)C and CaCl_(2).6H_(2)O +aq rarr CaCl_(2)(aq), DeltaH^(Theta) 19 kJ mol^(-1) at 18^(@)C . Find the heat of hydration of CaCl_(2) to CaCl_(2). 6H_(2)O by H_(2)O (g) . The Heat of vaporisation of water may be taken as 2452 J mol^(-1) at 18^(@)C .