H2 pKa

JChem does not provide a pK_a value for H₂ or a dynamic pK_b value for H^–.

Hi Bob, two questions here:

What are the experimental values for the pK_a of H₂ or the pK_b of H ^- ?

Which solvens for these values ?

Regards, Hans-Ulrich

David Evans' pKa table says "~36" in H₂O.  He doesn't give a reference.  I haven't found a reference for it in a cursory Web or SciFinder search.

Hi Bob,

thank you for the information and especially for the table. There is the sentence below the value for H₂ pKa ~36: "Values for ... water > 14   ... were extrapolated using various methods". I will discuss this topic with my colleagues.

Best regards, Hans-Ulrich

Thank you for all the information. We will implement this in a future release.

Zsolt

Hi,

 

The pKa value of H2  in water , pKa = 22.0  ± 2.   

Reference: Phys. Chem.Chem.Phys., 2001, 3, 2086-2090

 

Jozsi

Seems low to me.  Won't NaH deprotonate DMSO, which has a pK_a of about 30?

Hi,

 

pKa of DMSO is about 30, It is ok.

The pKa of H2 in DMSO is:  pKa = 34 ± 4.This pKa value is given  in the same reference as above.

DMSO can be deprotnated  with NaH according to these pKa values

 

Jozsi

We reconsidered this request, and it won't be implemented. Sorry for the inconvenience.