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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
The salt prepared by the method of direct combination is _______.
Write a balanced equation for the preparation of the following salt:
Zinc carbonate from zinc sulphate.
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.
Rock salt is mined just like ______.
What happens when a concentrated solution of sodium chloride (brine) is electrolysed? Write the equation of the reaction involved.
Why is the electrolysis of a concentrated solution of sodium chloride known as chlor-alkali process?
The products of chloro-alkali process are ______.
Which of the following salts will give an aqueous solution having pH of almost 7?
Consider the following salts:
Na2CO3, NaCl, NH4Cl, CH3COONa, K2SO4, (NH)2SO4
Which of these salts will give:
- acidic solutions?
- neutral solutions?
- basic solutions (or alkaline solutions)?
Define the following term:
Efflorescence
Taking sodium carbonate as an example, give the meaning of the following terms:
Water of crystallization
Name a colourless gas which bleaches.
Salts A, B, C, D and E undergo reactions (i) to (v) respectively. Identify the anion present in these salts on the basis of these reactions.
- When silver nitrate solution is added to a solution of A, a white precipitate, insoluble in dilute nitric acid, is formed.
- The addition of dilute hydrochloric acid to B produces a gas which turns lead acetate black on paper.
- When a freshly prepared solution of ferrous sulphate is added to a solution of C and concentrated sulphuric acid is gently poured from the side of the test tube, a brown ring is formed.
- When dilute sulphuric acid is added to D, a gas is produced which turns acidified potassium dichromate solution from orange to green.
- The addition of dilute hydrochloric acid to E produces effervescence. The gas produced turns lime water milky but does not affect acidified potassium dichromate solution.
Many salts absorb water from the atmosphere. This property is called:
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 | |
How many grams of Magnesium Sulphate are present in 135g of solid left by evaporation of sea water?
The chemical name of plaster of Paris is ______.
Acids react with metallic oxides to produce ______.
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:
Copper sulphate
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
