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प्रश्न
What are the two necessary conditions for rusting of iron?
उत्तर
Conditions for rusting:
- Presence of moisture (water).
- Presence of oxygen (air).
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संबंधित प्रश्न
Fill in the blank space by choosing the correct word from the given list.
List: oxygen, carbonic, suIphurUioxide gas, precipitation, helium
Solution of carbon dioxide in water is called _________ acid.
Tick (√) the most appropriate answer.
The humans pollute the air by :
Briefly state the importance of Water vapour.
The diagrams below represents an experiment to show the presence of a component of air.
- State why air is sucked from – outlet ‘B’ and not from outlet “A”
- State why the air is sucked ‘slowly’ from the outlet “B”
- State the observation seen after completion of the experiment.
- State the reason for the above observation seen.
- Name another component which if present in air as a pollutant would have given a similar observation
Name the following:
The main, rare (inert) gas present in air.
Which gas in the atmosphere is essential for respiration?
Assertion: Carbon dioxide occurs as carbonates in nature.
Reason: Carbon dioxide can exist as a liquid at atmospheric pressure.
Boojho took an empty plastic bottle, turned it upside down, and dipped its open mouth into a bucket filled with water. He then tilted the bottle slightly and made the following observations.
(i) Bubbles of air came out from the bottle.
(ii) Some water entered the bottle.
(iii) Nitrogen gas came out in the form of bubbles and oxygen got dissolved in water.
(iv) No bubbles formed, only water entered the bottle.
Which observations is/are correct?
Make sentences using the given set of words.
99%, oxygen, nitrogen, and air, together
Observe the picture given in Fig. carefully and answer the following questions.
What is covering the nose and mouth of the police man?
