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प्रश्न
How would you show that hydrogen is lighter than air?
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उत्तर
Take a delivery tube and place one of its ends in a soap solution kept in a trough and the other one in a flat bottom jar as shown in the figure. The soap bubbles containing hydrogen rise upward the air. The rising soap bubbles prove that hydrogen is lighter than air.

Hydrogen-filled soap bubbles rising upward in the soap solution and into the air shows that hydrogen is lighter than 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.
Multiple Choice Question
In metal activity series the more reactive metals are at
TRUE \ FALSE
Lead reacts briskly with dilute hydrochloric acid to form hydrogen.
Name the impurities present in hydrogen prepared in the laboratory.
How can these impurities be removed?
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.
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 balanced equation for the following conversion:
Zinc to sodium zincate – using an alkali.
Give balanced equation for the following conversion:
Acidified water to hydrogen – by electrolysis.
Give a balanced equation for the following conversions sodium plumbite from lead.
Give a balanced equation for the following conversions sodium aluminate from aluminium.
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.
In the laboratory preparation of hydrogen from zinc and dil. acid. Give a reason for the following:
The lower end of the thistle funnel should dip below the level of the acid in the flask.
Name the following.
A gaseous reducing agent which is basic in nature.
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.
