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प्रश्न
Give reason for the following:
Though hydrogen is lighter than air it cannot be collected by downward displacement of air.
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उत्तर
Since hydrogen is lighter than air. it is possible to collect the gas by downward displacement of air. But it is not safe to do so since a mixture of hydrogen and air can lead to an explosion.
संबंधित प्रश्न
Which metal is preferred for the preparation of hydrogen?
from water?
Why nitric acid is not used in the preparation of hydrogen?
Give a reason for the following:
Zinc granules are used in the lab preparation of hydrogen.
Give reason for the following:
Dilute sulphuric acid cannot be replaced by concentrated acid in the preparation of hydrogen.
Hydrogen may be prepared in the laboratory by the action of a metal on an acid.
Which of the acids dilute sulphuric, concentrated sulphuric, dilute nitric acid and concentrated nitric acid would you choose? Explain why you would not use the acids you reject.
Why are the following metals not used in the lab preparation of hydrogen?
calcium
Complete and balance the following reaction.
Na + H2O →_____________ +___________
Give reason:
A candle brought near the mouth of a jar containing hydrogen gas starts burning but is extinguished when pushed inside the jar.
Correct the following statement:
Hydrogen is separated from CO by passing the mixture through caustic potash solution.
Give reason for the following:
In the preparation of hydrogen by electrolysis of water – the distilled water used is acidified.
Select the correct options for the following statement:
The acid _____ is not Used in the laboratory preparation of hydrogen, using zinc and an acid.
Complete and balance the equation:
[General method]
Reactions of active metals - cold water
Sodium - 2Na + 2H2O → ______+ _______ [g]
Complete and balance the equation:
[General method]
Reactions of metals with dilute acids
Iron - Fe + 2HCl → ______ + _______ [g]
Complete and balance the equation:
[General method]
Reactions of metals - alkali [conc. soln.]
Aluminium - 2Al + 2NaOH + 2H2O → ______ + _______ [g]
2Al + 2KOH + 2H2O → _____ + _____ [g]
Account for the following fact:
Though lead is above hydrogen in the activity series, it does not react with dilute hydrochloric acid or dilutes sulphuric acid.
State the electronic configuration of hydrogen [at. no. 1].e
Give a reason why hydrogen can be placed in group 1 [1A] and group 17 [VIIA] of the periodic table.
State the reactant added to hydrogen to obtain the respective product in following case.
Hydrogen sulphide
Select the correct answer to the reactant added, to give the product in the preparation of hydrogen gas.
\[\ce{MgO + H2}\]
Give a reason for the following.
Granulated zinc is preferred to metallic zinc in the preparation of hydrogen using dilute acid.
