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प्रश्न
Give a test to differentiate between two gas jars – one containing pure hydrogen and the other hydrogen-air mixture.
Compare the combustibility of –
(a) pure hydrogen
(b) hydrogen-air mixture.
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उत्तर १
When a burning splinter is brought near the gas jar containing, pure H2 bums with pale blue flame quietly.
H2 + Oxygen mixture bums with explosion.
उत्तर २
Combustibility of :
(a) Pure hydrogen: Bums quietly in air with a pale blue flame forming water
2H2 + O2 → 2H2O
(b) Hydrogen air mixture: It explodes on burning.
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:
Define catalytic hydrogenation.
Multiple Choice Question
Hydrogen is responsible for producing
MULTIPLE CHOICE QUESTIONS
Which is the lightest of all elements?
- hydrogen
- helium
- lithium
- none of these
FILL IN THE BLANK
In nature, hydrogen occurs as a .................. molecule represented as H2
FILL IN THE BLANK
The compounds of carbon and hydrogen are called .................
FILL IN THE BLANK
Hydrogen is present abundantly in the ................
Write the balanced equation and give your observation when the following metal reacts:
Calcium with cold water
Write the balanced equation and give your observation when the following metal reacts:
Magnesium with steam
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).
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 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 |
What do the following symbols [or formula] denote : 2H ; H2 ; H+. [two atoms, molecule, ion]
How can you obtain hydrogen from sodium hydroxide [not by electrolysis].
Write balanced equation for the following reaction:
magnesium + dil. hydrochloric acid → ___
Write a correctly balanced equation for the following:
When steam is passed over red hot iron.
Explain the following:
Two jars of H2 are collected – “one burns quietly and the other does not”.
Describe one chemical test applied to the following gases, which would enable you to distinguish between them :‘carbon monoxide and hydrogen’.
Write down the “word equation” for the following reaction:
sodium hydroxide solution + zinc → ?
What do you observe when a piece of sodium is dropped into cold water?
Write balanced equation of the reaction in the preparation of : hydrogen from a solution of potassium hydroxide [other than by electrolysis].
Select the correct answer from the symbol in the bracket.
The element, which like hydrogen has one valence electron.
