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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 reacts with metal oxides to form ............and....................
Match the statements in Column A with those in Column B.
| Column A | Column B |
|
1. A metal which reacts with cold water to from hydrogen. |
1. Reduction |
| 2. A gas which is inflammable and non-supporter of combustion | 2. Hydrogenation |
|
3. A process in which vanspati ghee is prepared from vegitable oils |
3. oxidation |
|
4. The removal ofhydrogen or addition of oxygen |
4. sodium |
| 5. The addition of hydrogen or removal of oxygen | 5. Hydrogen |
Multiple Choice Question
Water gas is a mixture of
FILL IN THE BLANK
........................... means ‘maker of water’ in Greek.
How do different metals displace hydrogen from water? Explain with the help of equations.
For laboratory preparation of hydrogen, give the following:
fully-labeled diagram
Why nitric acid is not used in the preparation of hydrogen?
Hydrogen can be prepared with the help of cold water. Give a reaction of hydrogen with:
A monovalent metal
Give reason:
A candle brought near the mouth of a jar containing hydrogen gas starts burning but is extinguished when pushed inside the jar.
‘Hydrogen is obtained by electrolysis of acidified water’.
Answer the following pertaining to the preparation of hydrogen by electrolysis,
The meaning of the term ‘electrolysis’ and ‘electrolyte’.
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 metal which reacts with steam liberating hydrogen & the reaction is reversible.
Select the correct options for the following statement:
The metallic compound formed when a metal above aluminium in the activity series reacts with steam.
Select the correct options for the following statement:
The product formed on combustion of hydrogen in air is ___.
Complete and balance the equation:
[General method]
Reactions of metals with steam
Zinc - Zn + H2O → ______+ _______ [g]
Complete and balance the equation:
[General method]
Reactions of metals with dilute acids
Iron - Fe + 2HCl → ______ + _______ [g]
Select the correct answer to the reactant added, to give the product in the preparation of hydrogen gas.
\[\ce{Al2(SO4)3 + H2}\]
Give a balanced equation for the following conversion.
\[\ce{NH3<-H2->H2S}\]
