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प्रश्न
The aqueous solution of one of the following salts will turn phenolphthalein indicator pink. This salt is:
विकल्प
KCl
K2SO4
K2CO3
KNO3
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उत्तर
K2CO3
Explanation:
Phenolphthalein turns pink only in a basic (alkaline) solution with a pH greater than 8.2. Potassium carbonate (K2CO3) is a basic salt formed from a strong base (KOH) and a weak acid (H2CO3). When dissolved in water, it undergoes anionic hydrolysis, releasing excess hydroxide ions (OH−), thereby increasing the pH and triggering the pink colour change.
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संबंधित प्रश्न
From the list of the following salts choose the salt that most appropriately fits the
description is given in the following:
[AgCl, MgCl2, NaHSO4, PbCO3, ZnCO3, KNO3, Ca(NO3)2]
On heating, this salt gives a yellow residue when hot and white when cold
Write a balanced equation for the preparation of the following salts:
Copper sulphate from copper carbonate.
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.
Write the chemical name and formula of common salt.
What are the two main ways in which common salt (sodium chloride) occurs in nature?
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 a salt?
The products of chloro-alkali process are ______.
Which of the following salts will give an aqueous solution having pH of almost 7?
Give one example of a salt which gives an aqueous solution having:
pH more than 7
Write the name and formula of one salt which contains:
Five molecules of water of crystallisation.
Hard water required for an experiment is not available in a school laboratory. However, following salts are available in the laboratory. Select the salts which may be dissolved in water to make it hard for the experiment.
|
(1) |
Calcium Sulphate |
(2) |
Sodium Sulphate |
|
(3) |
Calcium Chloride |
(4) |
Potassium Sulphate |
|
(5) |
Sodium Hydrogen Carbonate |
(6) |
Magnesium Chloride |
(A) 1, 2 and 4
(B) 1, 3 and 6
(C) 3, 5 and 6
(D) 2, 4 and 5
Name two carbonates which do not produce carbon dioxide on heating.
Distinguish by a chemical test sodium chloride and sodium sulphide.
Differentiate hydrate and anhydrous salts with examples.
Sodium carbonate is a basic salt because it is a salt of a ____________.
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 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 :
