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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
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:
Copper sulphate from Copper Carbonate.
How is common salt obtained from sea-water?
Name three chemicals made from common salt (or sodium chloride).
What name is given to the common salt which is mined from underground deposits? How was this salt formed?
What will be the colour of litmus in an aqueous solution of ammonium chloride salt?
Give one example of a salt which gives an aqueous solution having:
pH less than 7
Consider the following salts:
Na2CO3, NaCl, NH4Cl, CH3COONa, K2SO4, (NH4)2SO4
Which of salts will give:
acidic solutions?
Write the name and formula of one salt each which contains:
five 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 liberate CO2 when reacted with sodium carbonate?
State what would you observe when :
The salt ferric chloride is exposed to the atmosphere.
Name two carbonates which do not produce carbon dioxide on heating.
Name a colourless gas which bleaches.
Distinguish by a chemical test sodium hydroxide solution and ammonium hydroxide solution.
The Salt Story
From: The New Indian Express 9 March 2021
The salt pans in Marakkanam, a port town about 120 km from Chennai are the third largest producer of salt in Tamil Nadu. Separation of salt from water is a laborious process and the salt obtained is used as raw materials for manufacture of various sodium compounds.
One such compound is Sodium hydrogen carbonate, used in baking, as an antacid and in soda acid fire extinguishers.
The table shows the mass of various compounds obtained when 1litre of sea water is evaporated.
| COMPOUND | FORMULA | MASS OF SOLID PRESENT /g |
| Sodium Chloride | NaCl | 28.0 |
| Magnesium Chloride | MgCl2 | 8.0 |
| Magnesium Sulphate | MgSO4 | 6.0 |
| Calcium Sulphate | CaSO4 | 2.0 |
| Calcium Carbonate | CaCO3 | 1.0 |
| TOTAL AMOUNT OF SALT OBTAINED | 45.0 | |
What is the pH of the acid which is used in the formation of common salt?
A salt that is formed by the complete neutralization of an acid and a base is called ______ salt.
Salt which is formed by the partial replacement of hydrogen ions of an acid by a metal is called ______.
Name the salt formed when sulphuric acid is added to sodium hydroxide and write its pH.
An aqueous solution of a salt turns blue litmus to red. The salt could be the one obtained by the reaction of ______.
