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प्रश्न
The metal salt A is blue in colour. When salt A is heated strongly over a burner, then a substance B is eliminated and a white powder C is left behind. When a few drops of a liquid D are added to powder C, it becomes blue again. What could be A, B, C and D?
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उत्तर
A is copper sulphate pentahydrate, CuSO4.5H2O; B is water of crystallisation, 5H2O; C is anhydrous copper sulphate, CuSO4; D is water, H2O.
The blue colour of copper sulphate is due to the presence of 5 water molecules. When copper sulphate crystals are heated, they lose their water molecules and turn into a grey-white powder known as anhydrous copper sulphate. The chemical équation for this process is:
\[\ce{CuSO4 * 5H2O -> CuSO4 + 5H2O}\]
After adding a few drops of water (D), the anhydrous copper sulphate rehydrates into copper sulphate pentahydrate, and due to the re-entry of water molecules into its crystal lattice, it becomes blue again. The chemical equation for this process is:
\[\ce{CuSO4 + 5H2O -> CuSO4 * 5H2O}\]
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संबंधित प्रश्न
From the list of the following salts choose the salt that most appropriately fits the
description is given in the following:
[AgCl, MgCl2, NaHSO4, PbCO3, ZnCO3, KNO3, Ca(NO3)2]
On heating this salt, a brown colored gas is evolved.
Write a balanced equation for the preparation of the following salts:
Copper sulphate from copper carbonate.
Write a balanced equation for the preparation of the following salt:
Zinc carbonate from zinc sulphate.
State whether the following statement is true or false:
Copper sulphate crystals are always wet due to the presence of water of crystallisation in them.
What name is given to the common salt which is mined from underground deposits? How was this salt formed?
Name the raw material used for the production of caustic soda.
What will be the colour of litmus in an aqueous solution of ammonium chloride salt?
The products of chloro-alkali process are ______.
Give one example of a salt which gives an aqueous solution having:
pH less than 7
What is a ‘salt’?
You are asked to prepare hard water in your laboratory. Select a group from the following groups of salts, any salt of which you may dissolve in distilled water to obtain hard water.
(A) NaCl; Na2SO4; KCl
(B) NaCl; CaCl2; KCl
(C) CaCl2; CaSO4; MgSO4
(D) Na2SO4; CaSO4; MgSO4
Hard water required for an experiment is not available in a school laboratory. However, following salts are available in the laboratory. Select the salts which may be dissolved in water to make it hard for the experiment.
|
(1) |
Calcium Sulphate |
(2) |
Sodium Sulphate |
|
(3) |
Calcium Chloride |
(4) |
Potassium Sulphate |
|
(5) |
Sodium Hydrogen Carbonate |
(6) |
Magnesium Chloride |
(A) 1, 2 and 4
(B) 1, 3 and 6
(C) 3, 5 and 6
(D) 2, 4 and 5
State one observation for each of the following :
Lead nitric is heated strongly in a test tube.
Name the particles present in :
Strong electrolyte
Give four substances which contain water of crystallization and write their common name.
Name gases which has a sour taste.
Distinguish by a chemical test sodium carbonate and sodium sulphite.
The chemical name of plaster of Paris is ______.
The acid reacts with a base to form a neutral product called ______.
