[a confused chiral girl]

hi 

I am looking for one of the energy diagrams that represents the reaction with the largest equilibrium constant between reactants and products. I know it cannot be #4, because that is an endothermic reaction, and Keq would be <1.

Since I am looking for the largest eq. constant, then I need to find one that is exothermic. So I am contemplating between 1 , 2. I also know that 3 cannot be it, because the Activation energy is lower as compared to the activation energy in 1 and 2. but I am unsure how to compare 1, and 2. Please help if you know which one has the largest eq. constant.

Thanks!

[a confused chiral girl]

may I ask if we need to look at the transition state in order to determine it? or simply the energy of the points where it says "reactants" and "products"?

[Yggdrasil]

The equilibrium constant depends only on the relative energies of the products and reactants.  You do not need to consider the energies of the transition states as these are only important for determining the kinetics of the reaction.  The energies of the transition states are not important for determining the overall thermodynamics of the reaction.

[a confused chiral girl]

thanks for your reply 

so in this case, would it be the second graph that has the greatest equilibrum constant, because the energy difference between the products and reactants is largest and it is also exothermic. is this reasoning right?

thanks!

[Yggdrasil]

Sounds good to me.