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प्रश्न
Give a reason for the following.
Hydrogen is collected by the downward displacement of water and not of air, even though it is lighter than air.
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उत्तर
Hydrogen is collected by the downward displacement of air because of
- It is insoluble in water.
- It forms an explosive mixture with air.
संबंधित प्रश्न
Thin strips of magnesium, copper, and iron are taken.
Arrange these metals in descending order of reactivity.
Based on the reactions of water on metals, arrange the following metals in increasing order of reactivity: iron, sodium, magnesium, zinc, calcium
Give reason for the following:
Potassium and sodium are not used for reaction with dilute hydrochloric acid or dilute sulphuric acid in the laboratory preparation of hydrogen.
When hydrogen is passed over a black solid compound A, the products are a 'colorless liquid' and a 'reddish-brown metal B'.
Substance B is divided into two parts each placed in separate test tubes.
Dilute HCl is added to one part of substance B and dilute HNO3 to the other.
- Name the substances A and B.
- Give two tests for the colourless liquid formed in the experiment.
- What happens to substance A when it reacts with hydrogen? Give reasons for your answer.
- Write an equation for the reaction between hydrogen and substance A.
- Is there any reaction between substance B and dilute hydrochloric acid? Give reasons for your answer.
Select the odd one out and justify your answer.
Fe, Zn, Cu and Mg
Select the odd one out and justify your answer.
Fe, Pb, Al and Zn
Choose terms from the options given in brackets to complete this sentence.
Sodium ………………. reacts smoothly with cold water.
(metal, amalgam, in the molten state)
What do you observe when dilute sulphuric acid is added to Zinc granules.
Give a chemical test to distinguish between the following gases:
Hydrogen chloride and hydrogen sulphide
Using dilute sulphuric acid how would you differentiate between:
Copper and magnesium
How would you identify the gaseous products evolved.
