Define water of crystallization? Give the chemical formula for two compounds as examples? How can it be proved that the water of crystallization makes a difference in the state and color of the compounds?

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Solution

The water of crystallization:
It is the fixed number of water molecules present in one formula unit of salt.
For examples:
CuSO₄.5H₂O (Copper sulfate Penta hydrate) Blue vitriol.
FeSO₄.7H₂O (Ferrous sulfate heptahydrate) Green vitriol.

By heating these salts they lose their water molecules and hence result in a change in state and color taking place.
Blue vitriol is blue as it contains 5 molecules of water of crystallization.
When it is heated, it loses water of crystallisation and becomes anhydrous copper sulfate (CuSO₄) which is grey-white.
On heating green vitriol, anhydrous ferrous sulfate (FeSO₄) is formed, which is white.
Anhydrous ferrous sulfate (FeSO₄)on further heating, decomposes into ferric oxide (Fe₂O₃), Sulfur dioxide (SO₂), and sulfur trioxide (SO₃) gas is released.

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Similar questions

(a) Define ‘water of crystallization’.

(b) Give two examples of substances having water of crystallization. Write their chemical formulae.

what is water of crystallization? write the common name and chemical formula of a commercially important compound which has ten water molecules a s water of crystallization. how is this compound obtained? write the chemical equation also. list any two uses of this compound.

Q. State the term : (Do not give examples)
(e) When a compound loses its water of crystallization on exposure to dry air

Q. Copper sulphate crystals which seem to be dry contain water of crystallization. When we heat the crystals, this water is removed and the salt turns white. If you moisten the crystals again with water, you will find that blue colour of the crystals reappears.

The water of crystallization is the fixed number of water molecules present in one formula unit of a salt. Five water molecules are present in one formula unit of copper sulphate. The chemical formula for hydrated copper sulphate is

C u {S O}_{4}

5 H_{2} O

. Now you would be able to answer the question whether the molecule of

{N a}_{2} {C O}_{3}

10 H_{2} O

is wet. One other salt, which possesses water of crystallization is gypsum. It has two water molecules as a water of crystallization. It has the formula

C a {S O}_{4}

2 H_{2} O

What are the uses of this salt?

Q. When the formula of a compound is given how to predict its crystal structure ? don't give examples .
write the rules to be followed.

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