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प्रश्न
Draw neat labelled diagrams for two different experiments to prove that – hydrogen is lighter than air.
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उत्तर
Experiment 1
Procedure: Bubble hydrogen gas by means of a small pipe into a dish containing soap solution.
Observation: Soap bubbles filled with H2 rise upwards.
Conclusion: Hydrogen is lighter than air hence soap bubbles filled with hydrogen rise up.
Experiment 2
Procedure: Take two dry test tubes.
Test tube 'A' - Filled with hydrogen.
Test tube 'B' - Filled with air.
Place test tube 'B' over test tube 'A' and test the gas in the upper test tube 'B' with a glowing splinter.
Observation: A 'pop' sound is heard in test tube 'B'. [hydrogen burns with a 'pop' sound].
Conclusion: Hydrogen is lighter than air and has moved upwards displacing the air.
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संबंधित प्रश्न
Indicate which of the following statement is true and which is false:
Zinc can liberate hydrogen from water, acid and alkali solution.
Name the following:
A metallic oxide which can be reduced into metal by hydrogen.
Draw a neat and well-labelled diagram for the laboratory preparation of hydrogen.
Multiple Choice Question
In metal activity series the more reactive metals are at
FILL IN THE BLANK
Sodium liberates hydrogen when treated with cold .............
Why is granulated zinc preferred in the laboratory preparation of hydrogen?
Name the impurities present in hydrogen prepared in the laboratory.
How can these impurities be removed?
Give reason:
Apparatus for laboratory preparation of hydrogen should be airtight and away from a naked flame.
Starting from zinc how would you obtain hydrogen using a dilute acid.
[Give balanced equation & name the product formed in the case other than hydrogen].
Name a metal which will not react with the reactants above to give hydrogen.
Starting from zinc how would you obtain hydrogen using an alkali.
[Give balanced equation & name the product formed in the case other than hydrogen].
Name a metal which will not react with the reactants above to give hydrogen.
In the laboratory preparation of hydrogen from zinc & dilute hydrocholoric acid – state a reason for the addition of traces of copper [II] sulphate to the reaction medium.
In the laboratory preparation of hydrogen from zinc & dilute hydrocholoric acid – state a reason for the collecting the hydrogen by downward displacement of water and not air & collecting it after all the air in the apparatus is allowed to escape.
Give reason for the following:
Copper does not displace hydrogen from dilute hydrochloric acid, but zinc does.
Give reason for the following:
In the laboratory preparation of hydrogen from zinc and dilute hydrochloric acid – the zinc used granulated zinc.
In the laboratory preparation of hydrogen from zinc and dil. acid. Give a reason for the following:
Dilute nitric acid is not preferred as the reactant acid.
The diagram represent the preparation and collection of hydrogen by a standard laboratory method.
State what difference will be seen if pure zinc is added in the distillation flask ‘X’ instead of granulated zinc.
The diagram represent the preparation and collection of hydrogen by a standard laboratory method.
Name a solution which absorbs the impurity – `"H"_2"S"`
The diagram represent the preparation and collection of hydrogen by a standard laboratory method.
State, why hydrogen is collected after all the air in the apparatus, is allowed to escape.
