[vhpk]

I have a question from my textbook regarding the temperature and Ka.
The Ka of CH_3COOH and CF₃COOH are 4.75 and 0.23 respectively, and nearly independent of temperature. Suggest reason for this?
I really have no idea for this question? Can you help me with this?
Thank you

[renge ishyo]

The equation for the temperature dependence of an equilibrium constant is given by the Van T' Hoff equation (source: http://en.wikipedia.org/wiki/Equilibrium_constant):

d(ln[K_eq])/dT =  :delta: H/RT²

If the change in the enthalpy (:delta: H) is very small then you would predict that the change in the equilibrium constant will also be small. :delta: H happens to be very small for acetic acid at -0.41 kJ mol^-1 (source: http://en.wikipedia.org/wiki/Acid_dissociation_constant ; scroll down to the thermodynamics table to compare this value to other acids in the table).

[vhpk]

Thank you for the reply