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प्रश्न
A salt X when dissolved in distilled water gives a clear solution which turns red litmus blue. Explain the phenomenon.
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उत्तर
When salt X is dissolved in distilled water, it produces a solution that turns red litmus paper blue, indicating the solution is basic (alkaline). This happens because salt X is formed from a strong base and a weak acid. In water, the salt anion undergoes hydrolysis, producing OH− ions and making the solution basic. Sodium carbonate (Na2CO3) dissolved in water gives a basic solution and turns red litmus blue.
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संबंधित प्रश्न
Write the chemical name and formula of common salt.
Common salt is obtained from sea-water by the process of ______.
Complete and balance the following chemical equation:
\[\ce{NaCl_{(aq)} + H2O_{(l)} ->[Electricity]}\]
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 is meant by ‘a family of salts’? Explain with examples.
Write the names, formulae and colours of any two hydrated salts.
What will be the colour of litmus in an aqueous solution of ammonium chloride salt?
A salt is dissolved in water and the pH of this salt solution is measured with a universal indicator paper. If the pH of solution is less than 7, the salt is most likely to be ______.
How many molecules of water of crystallisation (per formula unit) are present in:
Copper sulphate crystals
Name a salt whose solubility decreases with temperature.
You are asked to prepare hard water in your laboratory. Select a group from the following groups of salts, any salt of which you may dissolve in distilled water to obtain hard water.
(A) NaCl; Na2SO4; KCl
(B) NaCl; CaCl2; KCl
(C) CaCl2; CaSO4; MgSO4
(D) Na2SO4; CaSO4; MgSO4
State one observation for each of the following :
Lead nitric is heated strongly in a test tube.
Define the following term:
Hygroscopy
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?
Distinguish by a chemical test sodium hydroxide solution and ammonium hydroxide solution.
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.
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?
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
