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States of Matter — Chemistry STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceChemistryStates of Matter2 Marks
Question
Why is moist air lighter than dry air?
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Answer

Moist air has water vapour which has lower vapour density $\Big(\frac{\text{Mol.wt}}{2}=\frac{18}{2}=9\Big)$ than dry air, which has vapour density equal to 14.4. That is why moist air is lighter than dry air. It, rises up and form clouds in sky.

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