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Question
Define the following term:
Hygroscopy
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Solution
It is the phenomenon by which substances absorb moisture from air, but only sufficiently so as to become wet.
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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?
One of the constituents of baking powder is sodium hydrogencarbonate. The other constituent is :
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You are provided with the list of chemicals mentioned below in the box:
| Sodium hydroxide solution, copper carbonate, zinc, hydrochloric acid, copper, dilute sulphuric acid, chlorine, iron |
Using suitable chemicals from the list given, write a balanced chemical equation for the preparation of the salt mentioned below:
Sodium zincate
Select the correct answer from A, B, C, D and E.
A compound which in the aqueous solution state, is neutral in nature.
