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प्रश्न
How is common salt obtained from sea-water?
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उत्तर
Common salt is obtained from seawater by the process of evaporation through the sun’s heat, which leaves behind crude common salt. Crude salt is further purified to remove impurities, as it contains other salts.
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संबंधित प्रश्न
Which of the following salt has a blue colour and why?
CuSO4.5H2O or CuSO4
Rock salt is mined just like ______.
Complete and balance the following chemical equation:
\[\ce{NaCl + NH3 + H2O + CO2 ->}\]
What happens when copper sulphate crystals are heated strongly? Explain with the help of an equation.
The aqueous solution of one of the following salts will turn phenolphthalein indicator pink. This salt is:
A salt whose aqueous solution will have a pH of more than 7 will be ______.
Give one example of a salt which gives an aqueous solution having:
pH equal to 7
name two salts which are acidic.
Name two salts which are neutral when dissolved in water.
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?
What is deliquescence? What name is given to the compounds exhibiting such property?
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?
Name two carbonates which do not produce carbon dioxide on heating.
Copy and complete the following table which refers to the action of heat on some carbonates:
| Carbonate | Colour of residue on cooling |
| Zinc Carbonate | |
| Lead carbonate | |
| Copper carbonate |
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.
Select the correct answer from A, B, C, D and E.
A compound which in the aqueous solution state, is neutral in nature.
