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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
A metal ______ hydrogen in the reactivity series gives hydrogen with ______.
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 QUESTIONS
Hydrogen burns in oxygen to form
- hydrogen sulphide
- nitrates
- water
- ammonia
Complete the following word equation:
Sodium hydroxide + zinc → hydrogen + _________
For laboratory preparation of hydrogen, give the following:
method of collection
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.
How did the name 'hydrogen' originate?
Hydrogen may be prepared in the laboratory by the action of a metal on an acid.
Which of the metals copper, zinc, magnesium or sodium would be the most suitable?
Starting from hydrogen gas how would you obtain a metal by reduction of its heated oxide.
Select the correct options for the following statement:
The metal which reacts with steam liberating hydrogen & the reaction is reversible.
Complete and balance the equation:
[General method]
Reactions of metals with steam
Iron - 3Fe + 4H2O ⇌ ______+ _______ [g]
Complete and balance the equation:
[General method]
Reactions of metals with dilute acids
Zinc - Zn + 2HCl → ______ + _______ [g]
Name an element whsich reacts violently with water at room temperature.
State why hydrogen is not prepared in the laboratory by the action of sodium with cold water.
State the condition and give balanced equation for the conversion of water gas to hydrogen – in the Bosch process.
State the reactant added to hydrogen to obtain the respective product in following case.
Ammonia
Select the correct answer to the reactant added, to give the product in the preparation of hydrogen gas.
\[\ce{MgO + H2}\]
