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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:
Nitric acid cannot be used to prepare hydrogen by its action on active metals.
Name the following:
A metallic oxide which can be reduced into metal by hydrogen.
Name the chemicals required to prepare hydrogen gas in the laboratory.
Multiple Choice Question
In metal activity series the more reactive metals are at
FILL IN THE BLANK
........................ zinc is preferred over pure zinc in the laboratory preparation of hydrogen.
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 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.
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.
Complete and balance the equation:
[Laboratory method]
By action of dilute acid on zinc
Zinc - Zn + 2HCl → _____ + _____ [g]
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.
Give a reason for the following.
Nitric acid in the dilute form is not used in the laboratory preparation of hydrogen from metals.
The diagram represent the preparation and collection of hydrogen by a standard
laboratory method.

State what is added through the thistle funnel ‘Y’
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.
The diagram represent the preparation and collection of hydrogen by a standard laboratory method.

Name a gas other than hydrogen collected by the same method.
