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प्रश्न
Define the following term:
Efflorescence
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उत्तर
It is the phenomenon by which hydrated salts, on exposure to dry air, lose their water of crystallization and crumble to powder.
संबंधित प्रश्न
Give any two uses of common salt (sodium chloride).
Common salt is obtained from sea-water by the process of ______.
How would you show that blue copper sulphate crystals contain water of crystallisation?
What happens when copper sulphate crystals are heated strongly? Explain with the help of an equation.
What happens when a few drops of water are added to anhydrous copper sulphate? Explain with the help of an equation.
What happens when a concentrated solution of sodium chloride (brine) is electrolysed? Write the equation of the reaction involved.
What is a salt?
Give the names and formulae of any two salts. Also name the acids and bases from which these salts may be obtained.
The number of molecules of water of crystallisation present in washing soda crystals is ______.
The aqueous solution of one of the following salts will turn red litmus to blue. This salt is:
Which of the following salts will give an aqueous solution having pH of almost 7?
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?
Write the name and formula of one salt which contains:
Two molecules of water of crystallisation.
The pH values of three solutions A, B and C are given in the table. Answer the folloiwng questions:
| Solution | pH value |
| A | 12 |
| B | 2 |
| C | 7 |
Which solution will have no effect on litmus solution?
Taking sodium carbonate as an example, give the meaning of the following terms:
Water of crystallization
Answer the following questions below, relating your answers only to salts in the following list:
Sodium chloride, anhydrous calcium chloride, copper sulphate-5-water.
(i) What is the name given to the water in the compound copper sulphate-5-water?
(ii) If copper sulphate-5-water is heated, the water is driven off leaving anhydrous copper sulphate. What is the colour of anhydrous copper sulphate?
(iii) By what means, other than heating, you can dehydrate copper sulphate-5-water and obtain anhydrous copper sulphate?
(iv) Which one of the salts in the given list is deliquescent?
State what would you observe when :
Washing soda crystals are exposed to the atmosphere.
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?
The chemical name of plaster of Paris is ______.
Salt is ______ in nature.
