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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.
Hydrogen is a good reducing agent: What do you understand by the above statement? Explain with the help of copper oxide as an example.
State four uses of hydrogen:
MULTIPLE CHOICE QUESTIONS
Which is the lightest of all elements?
- hydrogen
- helium
- lithium
- none of these
FILL IN THE BLANK
Hydrogen is present abundantly in the ................
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:
Magnesium with steam
Choose the correct option:
The composition of the nucleus of deuterium is
Give equations for the reactions.
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.
Chlorine is ______ to HCl.
Give balanced equation for the following conversion:
Iron [III] oxide to iron – using hydrogen.
Match the statements in List I with the appropriate answer in List II.
| List I | List II |
| 1. An atom of hydrogen | A: Chromic oxide |
| 2. A strong oxidising agent | B: Ammonia |
| 3. A promoter used in Bosch process | C: Iron |
| 4. A chemical used in the manufavture of fertilizers | D: One electron |
| 5. The catalyst used in production of a basic gas from nitrogen. | E: Dilute nitric acid |
How can you obtain hydrogen from sodium hydroxide [not by electrolysis].
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.
Give a reason for the following.
A mixture of hydrogen and chlorine can be separated by passage through a porous pot.
