I am studying the reaction of dissolved dioxygen with manganese(II) hydroxide for the Winkler method:


The data I have been given is Mn(OH)2's pKs=12.7, as well as the standard potential for MnO2(s)/Mn(OH)2(s), which is 1.23V, and the one of O2/H2O, which is also 1.23V; nothing more. Using Gibbs free energy for each half reaction, I have managed to calculate the quilibrium constant for the reaction at 298K, which I found to be 10^-25.4, making it dramatically unfavorable to products.

Does anyone find the same thing for this constant, or have I made a mistake? If it is the right constant, how come the reaction takes place?

I am aware that it is not the commonly used reaction when it comes to the Winkler method, but its the only one I can propose when it comes to having the dioxygen react with manganese hydroxide owing to what few data I have. Also sorry for my shaky English, I'm french.

Thanks in advance for your answers!


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.