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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
Fill in the blank
Hydrogen is ...................soluble in water.
A metal ______ hydrogen in the reactivity series gives hydrogen with ______.
Fill in the blank
Hydrogen reacts with metal oxides to form ............and....................
FILL IN THE BLANK
In electrolysis of water, dilute sulphuric acid is added to increase ..................of water.
For laboratory preparation of hydrogen, give the following:
materials used
Give a reason for the following:
Zinc granules are used in the lab preparation of hydrogen.
How did the name 'hydrogen' originate?
Hydrogen may be prepared in the laboratory by the action of a metal on an acid.
How would you modify your apparatus to collect dry hydrogen? Which drying agent would you employ for this purpose?
Complete and balance the following reaction.
Zn + NaOH →_____________ +___________
Correct the following statement:
Hydrogen is separated from CO by passing the mixture through caustic potash solution.
State how hydrogen occurs in the free state. Name three compounds containing hydrogen in the combined state.
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:
A foul smelling gas formed when hydrogen reacts with a molten non-metal, is ___.
Complete and balance the equation:
[General method]
Reactions of active metals - cold water
Calcium - Ca + H2O → ______+ _______ [g]
Complete and balance the equation:
[General method]
Reactions of metals with dilute acids
Magnesium - Mg + 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:
Potassium and sodium are not used to react with dilute ‘hydrochloric acid or dilute sulphuric acid in the laboratory preparation of hydrogen.
Give a balanced equation for obtaining hydrogen from?
Steam using a trivalent metal
Give a balanced equation for the following conversion.
\[\ce{KAlO2<-KOH->K2ZnO2}\]
Give a reason for the following.
Granulated zinc is preferred to metallic zinc in the preparation of hydrogen using dilute acid.
