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प्रश्न
What do you observe when a piece of sodium is dropped into cold water?
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उत्तर
When a piece of sodium metal dropped in cold water we observe: Sodium floats on water surface melts forming a silvery globule which darts about the surface of water catches fire and burns with golden yellow flame.
Bubbles of hydrogen evolve and solution is soapy, slightly warm (alkaline) hence turns red litmus blue.
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संबंधित प्रश्न
Indicate which of the following statement is true and which is false:
Hydrogen gas is easily liquefiable.
Give reason for the following:
Helium replaced hydrogen in weather observation balloons?
Multiple Choice Question
Hydrogen is
MULTIPLE CHOICE QUESTIONS
Which is the lightest of all elements?
- hydrogen
- helium
- lithium
- none of these
FILL IN THE BLANK
Ammonia is used to make ................
Write the balanced equation and give your observation when the following metal reacts:
Magnesium with boiling water
Give the balanced equation of the reaction.
How is hydrogen separated from carbon dioxide and carbon monoxide?
With reference to the equation : Cl2 + H2S → 2HCl + S pertaining to a redox reaction – select the correct answer.
Hydrogen sulphide is ______ to sulphur since the reaction involves ______ of hydrogen.
Give reason for the following:
The reaction of chlorine with hydrogen sulphide is deemed a redox reaction.
Select the correct options for the following statement:
The gas which has now replaced hydrogen in air balloons is ___.
Give a chemical test to distinguish between the following gases:
Hydrogen and oxygen
Give a chemical test to distinguish between the following gases:
Ammonia and hydrogen chloride
What do the following symbols [or formula] denote : 2H ; H2 ; H+. [two atoms, molecule, ion]
Name a gas which burns in air or oxygen forming water.
Write a correctly balanced equation for the following:
When steam is passed over red hot iron.
Describe one chemical test applied to the following gases, which would enable you to distinguish between them :‘carbon monoxide and hydrogen’.
How would you obtain ‘hydrogen from sodium hydroxide’ solution other than by electrolysis?
What do the following symbols represent : 2H and H2.
