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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:
The hydrogen molecule is monovalent.
Hydrogen is combustible as well as a supporter of combustion.
Give a balanced chemical equation for the reaction.
Hydrogen is a good reducing agent: What do you understand by the above statement? Explain with the help of copper oxide as an example.
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:
Sodium with cold water
Write the balanced equation and give your observation when the following metal reacts:
Calcium with cold water
Using a burning candle and a jar of hydrogen – how would you prove experimentally that Hydrogen does not support combustion.
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 balanced equation for the following conversion:
Water gas to hydrogen – industrially.
Write a correctly balanced equation for the following “word equation”:
calcium + water → calcium hydroxide + hydrogen
How can you obtain hydrogen from sodium hydroxide [not by electrolysis].
Write correctly the balanced equation for the following:
‘When zinc filings are added to a concentrated solution of sodium hydroxide’.
Write down the “word equation” for the following reaction:
sodium hydroxide solution + zinc → ?
Give balanced equation for obtaining hydrogen from cold water using a monovalent active metal.
Give balanced equation for obtaining hydrogen from cold water using a divalent active metal.
Give a reason for the following.
A mixture of hydrogen and chlorine can be separated by passage through a porous pot.
Select the correct answer from the symbol in the bracket.
The element, which like hydrogen has one valence electron.
