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प्रश्न
A solution of a substance ‘X’ is used for white washing Name the substance ‘X’ and write its formula.
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उत्तर
Calcium oxide CaO
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संबंधित प्रश्न
When carbon dioxide is passed through lime water, it turns milky due to the formation of ______.
FILL IN THE BLANK
In a double decomposition precipitation reaction both the reactants must be ............ soluble.
Define electrolysis.
Name three reducing agents ?
Match the pairs.
| a. | Photosynthesis | i. | Tendency to lose electrons |
| b. | Water | ii. | Reactant in combustion process |
| c. | Sodium chloride | iii. | Chemical change |
| d. | Dissolution of salt in water | iv. | Covalent bond |
| e. | Carbon | v. | Ionic bond |
| f. | Fluorine | vi. | Physical change |
| g. | Magnesium | vii. | Tendency to form anion |
Give an example of a reaction where the following are involved:
Close contact
Give an example of a reaction where the following are involved:
Solution
What do you observe? When
Barium chloride is added to sodium sulphate solution
Complete the following table and write your observations.
|
Hydrogen sulphide |
Ammonia |
Sulphur dioxide |
Hydrogen chloride |
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Shake the gas with red litmus solution |
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Shake the gas with blue litmus solution |
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Apply a burning splint to a gas |
Name: A brown gas
Write your observation and a balanced equation in the case of the following substances being heated.
Copper nitrate.
Select the correct answer for the following options:
The basic gas obtained when two gases react in presence of a catalyst and the reaction is exothermic.
Give balanced equation for the following conversion affected by heat alone on the substance:
Hydrated copper sulphate to sulphur dioxide
Complete the table given below.
| Heat on sodium chloride | Colour imparted to flame during flame test |
A chemical reaction is often accompanied by external indications or characteristics.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Ammonium dichromate.
Assertion: The formation of iron oxide from iron is a chemical change.
Reason: For the rust to form from iron, it must be exposed to air and water.
When an aqueous solution of potassium chloride is added to an aqueous solution of silver nitrate, a white precipitate is formed. Give the chemical equation of this reaction.
Give an example where heat, light, and sound are produced during a chemical change.
______ is the chemical name of limestone.
