Question

I am sitting in a room filled with oxygen and hydrogen as Usual, then why it doesn't rain????
since, H2+O2---> 2H2O

Answer 1

As per the fact hydrogen is present in very low quantity around us as a gas so its not possible to rain and if at all the hydrogen reacts with the free oxygen molecules there wouldn't be any oxygen left and we die for sure.
The hydrogen present in the atmosphere is present in the state of water already with combined oxygen and if at all the hydrogen gas is present it would present in the form of pollutants 
Hope it helps!!
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