Chemistry
Grade-8
Easy
Question
Why did helium replace hydrogen in weather observation balloons?
(i) It forms a mixture of air that can explode.
(ii) It is heavier than hydrogen.
(iii) It is very expensive to use hydrogen gas in balloons.
- Only (i) and (ii)
- Only (ii) and (iii)
- Only (i) and (iii)
- Only (i)
Hint:
It forms a mixture of air that can explode.
The correct answer is: Only (i)
If there is small leakage of hydrogen in a balloon, it forms a mixture with air that can explode. So helium has replaced hydrogen.
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