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प्रश्न
How can these impurities be removed?
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उत्तर
- The impurities can be removed from hydrogen by passing it through
- Silver nitrate solution to remove arsine and phosphine.
AsH3 + 6AgNO3 → Ag3As + 3AgNO3 + 3HNO3
PH3 + 6AgNO3 → Ag3P + 3AgNO3 + 3HNO3
- Lead nitrate solution to remove hydrogensulphide.
Pb(NO3)2 + H2S → Pbs + 2HNO3
- Caustic potash solution to remove sulphur dioxide, carbon dioxide and oxides of nitrogen.
SO2 + 2KOH → K2SO3 + H2O
CO2 + 2KOH→ K2CO3+ H2O
2NO2 + 2KOH →KNO2 + KNO3 + H2O
- A drying agent used to dry the gas. Common drying agents such as fused calcium chloride, caustic potash stick and phosphorus pentoxide remove water vapor.
So, the gas is purified and dried and then collected over mercury because mercury does not react with it.
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संबंधित प्रश्न
Indicate which of the following statement is true and which is false:
Nitric acid cannot be used to prepare hydrogen by its action on active metals.
Indicate which of the following statement is true and which is false:
Zinc can liberate hydrogen from water, acid and alkali solution.
Give reason for the following:
Nitric acid not used for the preparation of hydrogen gas?
Name the following:
A metallic oxide which can be reduced into metal by hydrogen.
How is hydrogen gas collected? Why?
How would you show that hydrogen is a non-supporter of combustion?
Multiple Choice Question
In metal activity series the more reactive metals are at
FILL IN THE BLANK
Sodium liberates hydrogen when treated with cold .............
Why is granulated zinc preferred in the laboratory preparation of hydrogen?
Name the impurities present in hydrogen prepared in the laboratory.
In the laboratory preparation of hydrogen from zinc & dilute hydrocholoric acid – state a reason for the addition of traces of copper [II] sulphate to the reaction medium.
In the laboratory preparation of hydrogen from zinc & dilute hydrocholoric acid – state a reason for the collecting the hydrogen by downward displacement of water and not air & collecting it after all the air in the apparatus is allowed to escape.
Give balanced equation for the following conversion:
Zinc to sodium zincate – using an alkali.
Give balanced equation for the following conversion:
Acidified water to hydrogen – by electrolysis.
In the laboratory preparation of hydrogen from zinc and dil. acid. Give a reason for the following:
Dilute nitric acid is not preferred as the reactant acid.
In the laboratory preparation of hydrogen from zinc and dil. acid. Give a reason for the following:
The lower end of the thistle funnel should dip below the level of the acid in the flask.
In the laboratory preparation of hydrogen from zinc and dil. acid. Give a reason for the following:
Hydrogen is not collected over air.
The diagram represent the preparation and collection of hydrogen by a standard laboratory method.
Name a solution which absorbs the impurity – `"H"_2"S"`
The diagram represent the preparation and collection of hydrogen by a standard laboratory method.
State, why hydrogen is collected after all the air in the apparatus, is allowed to escape.
The diagram represent the preparation and collection of hydrogen by a standard laboratory method.
Name a gas other than hydrogen collected by the same method.
