Are all exothermic reactions spontaneous?

1 Answer

Take the example of formation of water from Hydrogen, Oxygen this reaction highly exothermic but kinetically slow

Explanation:

The reaction to proceed first the reactants have to cross their activation energy barrier so that they form products giving the energy. Hence catalyst or temperature of the process plays a role in reaction to proceed spontaneously

The other example is burning of LPG gas requires ignition for reaction to gets started even though reaction is spontaneous.

Here is a video that explains spontaneity and signs of enthalpy and entropy: