[undercoverEng]

Hi, I'm corrently struggling with the determination of an equilibrium constant. The reaction is between N-ethylcarbazole (0H-NEC) and hydrogen:
6H₂ (g) +0H-NEC (l) 12H-NEC (l)
With the hydrogenation reaction being exothermic. I know that when there is a gas involved, the equilibrium constant depends on their pressure only, but how do I define this pressure? What I mean is that I have the partial pressure of the gas above the interface, through Henry's law I'm giving a guess on its concentration in the solution and now I need the hydrogen pressure above the catalyst (which sits at the bottom of the liquid). Does anyone know how to help me?

[Orcio_87]

I think that solubility of hydrogen in the liquid is dont important, as the catalyst will absorb it from solution one way or another. I mean - pressure above catalyst = pressure above the liquid.