How low is the low temperature? Is 25° C not high enough compared to others? Why is Delta G negative?

2H2(g) + O2(g) ----> 2H2O (g)
It is a combustion reaction so enthalpy change is negative.Entropy change is also negative as number of gaseous moles are decreasing from reactants to products.
This reaction is very spontaneous at low temperature becuase H2 (g) is very reactive and immediately undergoes oxidation even at low temperature.This means Gibb's free energy is negative for this reaction.25 degree C is low temperature for DG to be negative.This reaction is very spontaneous even at romm temperature and reason is reactivity of hydrogen gas.

Quote from: uma on April 15, 2024, 09:27:48 AM2H2(g) + O2(g) ----> 2H2O (g)
It is a combustion reaction so enthalpy change is negative.Entropy change is also negative as number of gaseous moles are decreasing from reactants to products.
This reaction is very spontaneous at low temperature becuase H2 (g) is very reactive and immediately undergoes oxidation even at low temperature.This means Gibb's free energy is negative for this reaction.25 degree C is low temperature for DG to be negative.This reaction is very spontaneous even at romm temperature and reason is reactivity of hydrogen gas.

But it need still a spark or flash. You can mix hydrogen and oxygen, without a spontanous reaction.

It gets the sparkfrom collisions among the molecules that is the reason we dont have H2 gas in the atmosphere and that is the reason we are still working how to make a battery of H2 and O2.

Quote from: uma on April 15, 2024, 06:50:07 PMIt gets the sparkfrom collisions among the molecules that is the reason we dont have H2 gas in the atmosphere and that is the reason we are still working how to make a battery of H2 and O2.

But only if the activation energy is high enough. In the atmosphere there is no H2, because there is no reaction to develop any. H2 is mainly man made by electrolysis or oil cracking refinery.

In comparison flourine and hydrogen ignites directly if mixed.

By using chlorine it needs a light Flash, in a darf room also nothing happens.

By using oxygen a spark , flame or also light Flash can ignite it.

Its because of different activation energy needed.

okay all that is not needed here in this question above.