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प्रश्न
Which test should be made before collecting hydrogen in a gas jar?
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उत्तर
Test: Collect some amount of gas in a test tube and take it to a flame.
If the gas burns quietly, then there is no more air in the flask.
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संबंधित प्रश्न
A metal ______ hydrogen in the reactivity series gives hydrogen with ______.
Hydrogen gas is collected by the downward displacement of water. Give reason ?
Give a reason for the following:
Zinc granules are used in the lab preparation of hydrogen.
Give reason for the following:
Purified and dried hydrogen is collected over mercury.
Why are the following metal not used in the lab. preparation of hydrogen?
iron
Why are the following metals not used in the lab. preparation of hydrogen?
sodium
On heating which of the following substances i.e. copper carbonate, zinc carbonate, washing soda, copper sulphate, zinc nitrate, copper nitrate, lead nitrate, ammonium chloride and ammonium dichromate – relate to the reaction given below.
An efflorescent substance which leaves a residue having the same colour as the substance and evolves a gas which changes the colour of cobalt chloride paper.
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 - alkali [conc. soln.]
Aluminium - 2Al + 2NaOH + 2H2O → ______ + _______ [g]
2Al + 2KOH + 2H2O → _____ + _____ [g]
Select the correct answer to the reactant added, to give the product in the preparation of hydrogen gas.
\[\ce{NaAlO2 + H2}\]
