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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.
Complete and balance the following equation:
H2+____________→ 2HCI
Give reason for the following:
Helium replaced hydrogen in weather observation balloons?
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 Question
Equal volumes of hydrogen and chlorine are exposed to diffused sunlight to prepare
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 ................
Why is hydrogen called a reducing agent? Give chemical equation to support your answer ?
Write the balanced equation and give your observation when the following metal reacts:
Calcium with cold water
Give the balanced equation of the reaction.
Choose terms from the options given in brackets to complete this sentence.
A metal …………….. hydrogen in the activity series gives hydrogen with …………… acid or …………… acid.
(above, below, dilute hydrochloric, concentrated hydrochloric, dilute sulphuric).
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.
With reference to the equation : Cl2 + H2S → 2HCl + S pertaining to a redox reaction – select the correct answer.
Chlorine acts as an ______ agent.
Give balanced equation for the following conversion:
Water gas to hydrogen – industrially.
Give balanced equation for the following conversion:
Iron [III] oxide to iron – using hydrogen.
Give balanced equation for the following conversion:
Nitrogen to a basic gas – using hydrogen.
Select the correct options for the following statement:
The gas which has now replaced hydrogen in air balloons is ___.
Explain the following:
Two jars of H2 are collected – “one burns quietly and the other does not”.
Complete and balance the following equations:
Al + NaOH + ____ → ____ + ____
