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प्रश्न
The number of molecules of water of crystallisation present in washing soda crystals is:
(a) five
(b) two
(c) ten
(d) seven
उत्तर
ten
The chemical formula of washing soda is Na2CO3.10H2O. The water molecules that form part of the structure of a salt are called its water of crystallisation. Hence, the number of molecules of water of crystallisation present in washing soda crystals is 10.
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संबंधित प्रश्न
Why is the electrolysis of a concentrated solution of sodium chloride known as chlor-alkali process?
Which of the following salts will give an aqueous solution having pH of almost 7?
(a) NH4NO3
(b) NH4Cl
(c) CaCl2
(d) KCl
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
When the concentrated aqueous solution of substance X is electrolysed, then NaOH, Cl2 and H2 are produced. Name the substance X. What is the special name of this process?
Give one example of a salt which gives an aqueous solution having:
pH equal to 7
What is a ‘salt’?
name two salts which are acidic.
State what would you observe when :
Washing soda crystals are exposed to the atmosphere.
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?
Salt which is formed by the partial replacement of hydrogen ions of an acid by a metal is called ______.
