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प्रश्न
Define the following term: Efflorescence.
उत्तर
Efflorescence: It is the phenomenon by which hydrated salts on exposure to dry air, lose their water of crystallization and crumble to powder.
संबंधित प्रश्न
Identify the substance underlined, in the following case
A solid formed by reaction of two gases, one of which is acidic and the other basic in nature
State what would you observe when Washing Soda Crystals are exposed to the atmosphere
The property by which certain hydrated salts, when left exposed to the atmosphere, lose their water of crystallization and crumble into powder.
State one relevant observation for the following:
Anhydrous calcium chloride is exposed to air for some time.
Write a balanced equation for the preparation of the following salts:
Zinc carbonate from Zinc sulphate
Which of the following salt has a blue colour and why?
CuSO4.5H2O or CuSO4
Write the chemical name and formula of common salt.
Why is the electrolysis of a concentrated solution of sodium chloride known as chlor-alkali process?
Name three products of the chlor-alkali process. State two uses of each of these products.
Consider the following salts:
Na2CO3, NaCl, NH4Cl, CH3COONa, K2SO4, (NH4)2SO4
Which of salts will give:
acidic solutions?
Consider the following salts:
Na2CO3, NaCl, NH4Cl, CH3COONa, K2SO4, (NH4)2SO4
Which of salts will give:
neutral solutions?
Explain ‘salt hydrolysis’
name two salts which are acidic.
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
Name the particles present in :
Strong electrolyte
Give four substances which contain water of crystallization and write their common name.
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.
Answer the questions below relating your answers only to salts in the following list: Sodium chloride, anhydrous calcium chloride, copper sulphate-5-water?
- What name is given to the water in the compound copper sulphate-5-water?
- If copper sulphate-5-water is heated, anhydrous coppersulphate is formed. What is its colour?
- By what means, other than healing, could you dehydrate copper sulphate-5-water and obtain anhydrous coppersulphate?
- Which one of the salts in the given list is deliquescent?
Copy and complete the following table which refers to the action of heat on the carbonate:
| Carbonate | Colour of residue on cooling |
| Zinc Carbonate |
One of the constituents of baking powder is sodium hydrogencarbonate. The other constituent is :
