Q.

A sample of hydrate of barium chloride weighing 61 g was heated until all the water of hydration was removed. The dried sample weighed 52 g. The formula of the hydrated salt is:    (Atomic mass of Ba = 137 amu, Cl = 35.5 amu).

1 BaCl2·H2O  
2 BaCl2·3H2O  
3 BaCl2·4H2O  
4 BaCl2·2H2O  

Ans.

(4)

BaCl2·xH2O  BaCl2+xH2O, (137+2×35.5+18x)=(208+18x) g/mole

208+18x208=6152,  52(208+18x)=61×208,

10816+936x=12688,  936x=1872,  x=2,  

Formula is BaCl2·2H2O