The crystalline salt Na₂SO₄.xH₂O on heating loses 55.9% of its weight. The formula of crystalline salt is (Kerala CEE 2007)

Hydrated salts lose water of crystallisation on heating and becomes anhydrous. The water of crystallisation is defined as the number of water molecules that are attached to the central metal atom without reacting. Given, Hydrated crystalline salt is 2 4 2 . Na SO xH O The molecular mass of hydrated salt is 2 23 32 4 16 18 46 32 64 18 x x x x 1 4 2 1 8 x ------ (1) Mass of water molecules = 18x -------(2) Mass percentage of water molecules is 55.9% (looses on heating) 18 55.9 142 18 100 1800 7937.8 1006.2 793.8 7937.8 7937.8 793.8 9.999748047 x x x x x x x