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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.
Give reason for the following:
Nitric acid not used for the preparation of hydrogen gas?
Name the following:
A metal which liberates hydrogen only when steam is passed over red hot metal.
Name the chemicals required to prepare hydrogen gas in the laboratory.
How is hydrogen gas collected? Why?
FILL IN THE BLANK
Sodium liberates hydrogen when treated with cold .............
Why is granulated zinc preferred in the laboratory preparation of hydrogen?
Under what conditions can hydrogen be made to combine with chlorine?
Name the products and write the equation for the reaction.
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 Steam.
[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.
Give balanced equation for the following conversion:
Zinc to sodium zincate – using an alkali.
Give reason for the following:
Copper does not displace hydrogen from dilute hydrochloric acid, but zinc does.
Give a balanced equation for the following conversions sodium plumbite from lead.
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"`
