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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
In electrolysis of water, dilute sulphuric acid is added to increase ..................of water.
MATCH THE COLUMNS
| column A | column B |
| 1. `""2H_2 + O_2 → 2H_2O` | A. This reaction is not possible |
| 2. `""H_2+CI_2 →2HCI` | B.This reaction is exothermic to the extent of explosion |
| 3.`""ZaO+ H^2→Zn +H_2O` | C.This reaction is known as Haber process |
| 4.`""Cu + H_2SO^4 → CuSO_4 + H_2 ` | D.This reaction illustrates the reducing property of bydrogen |
| 5.`""N_2 +3H_2 → 2NH_3 +heat ` | E. This reaction takes place in diffused sunlight |
| F. This reaction is a method of preparation of hydrogen |
Which metal is preferred for the preparation of hydrogen?
from acid?
For laboratory preparation of hydrogen, give the following:
chemical equation
Why hot concentrated sulphuric acid is not used in the preparation of hydrogen?
Give reason for the following:
Purified and dried hydrogen is collected over mercury.
Give reason for the following:
The end of the thistle funnel should be dipped under acid.
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.
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.
Fe + H2O →_____________ +___________
Complete and balance the following reaction.
Al + KOH + H2O→_____________ +___________
Select the correct options for the following statement:
The metal used as a catalyst in hydrogenation of oils.
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]
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.
Hydrogen chloride
State the reactant added to hydrogen to obtain the respective product in following case.
Water
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.
\[\ce{Ca(OH)2 + H2}\]
