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प्रश्न
What is meant by ‘hydrated’ salts? Explain with examples.
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उत्तर
The water molecules which form part of the structure of a crystal (of a salt) are called water of crystallisation. Salts that contain water of crystallisation are called hydrated salts.
Copper sulphate crystals contain 5 molecules of water of crystallisation in one formula unit and therefore are written as CuSO4.5H2O. It is called copper sulphate pentahydrate (Pentahydrate means five molecules of water).
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संबंधित प्रश्न
What are the two main ways in which common salt (sodium chloride) occurs in nature?
What name is given to the common salt which is mined from underground deposits? How was this salt formed?
Common salt is obtained from sea-water by the process of ______.
Complete and balance the following chemical equation:
\[\ce{NaCl_{(aq)} + H2O_{(l)} ->[Electricity]}\]
Name three products of the chlor-alkali process. State two uses of each of these products.
A salt whose aqueous solution will have a pH of more than 7 will be ______.
A salt is dissolved in water and the pH of this salt solution is measured with a universal indicator paper. If the pH of solution is less than 7, the salt is most likely to be ______.
Give one example of a salt which gives an aqueous solution having:
pH equal to 7
Name a salts whose solubility increases with temperature.
Name a salt whose solubility decreases with temperature.
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.
The pH values of three solutions A, B and C are given in the table. Answer the following questions:
| Solution | pH value |
| A | 12 |
| B | 2 |
| C | 7 |
- Which solution will have no effect on litmus solution?
- Which solution will liberate CO2 when reacted with sodium carbonate?
- Which solution will turn red litmus solution blue?
Fill in the blank
___________ is the phenomenon by which hydrated salts on exposure to dry air, lose their water of crystallization and crumble to powder.
State what would you observe when :
The salt ferric chloride is exposed to the atmosphere.
Name gases which has a sour taste.
Which of the following is not an acidic salt?
Salt is ______ in nature.
You are provided with the list of chemicals mentioned below in the box:
| Sodium hydroxide solution, copper carbonate, zinc, hydrochloric acid, copper, dilute sulphuric acid, chlorine, iron |
Using suitable chemicals from the list given, write a balanced chemical equation for the preparation of the salt mentioned below:
Ferric chloride
