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प्रश्न
Define the following term:
Hygroscopy
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उत्तर
It is the phenomenon by which substances absorb moisture from air, but only sufficiently so as to become wet.
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 gives a yellow residue when hot and white when cold
Write a balanced equation for the preparation of the following salts:
Copper sulphate from Copper Carbonate.
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.
Name the major salt present in sea-water.
Common salt is obtained from sea-water by the process of ______.
Rock salt is mined just like ______.
How would you show that blue copper sulphate crystals contain water of crystallisation?
Explain how anhydrous copper sulphate can be used to detect the presence of moisture (water) in a liquid.
What will be the colour of litmus in an aqueous solution of ammonium chloride salt?
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 phenolphthalein indicator pink. This salt is:
Which of the following salts will give an aqueous solution having pH of almost 7?
P and Q are aqueous solutions of sodium chloride and sodium hydroxide, respectively. Which of these will turn:
- blue litmus red?
- red litmus blue?
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?
State what would you observe when :
Washing soda crystals are exposed to the atmosphere.
Name two carbonates which do not produce carbon dioxide on heating.
Name the anion present in the following compound:
Compound A, when warmed with concentrated sulphuric acid, gives a gas which fumes in moist air and which gives dense white fumes with ammonia.
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?
The acid reacts with a base to form a neutral product called ______.
Select the correct answer from A, B, C, D and E.
A compound which in the aqueous solution state, is neutral in nature.
