Submitted by Joanne Stewart / Hope College on Thu, 03/31/2022 - 17:07
My Notes

This LibreTexts module by Dr. Tom Neils and Dr. Stephanie Schaertel provides a clear and thorough explanation of why some biochemistry and organic chemistry textbooks get the pKa of water wrong. The pKa of water at 25 ºC is 14.0 and not 15.7. This module describes the derivation of the correct value and describes why the value of 15.7 should not be used. 

Learning Goals

Students will be able to explain how to derive the correct value for the pKa of water.

Implementation Notes

This resource not only corrects a common error found in some textbooks, but it also provides a great example of how science knowledge is created and how difficult it can be to correct.

Evaluation Methods

Not only could this be used to teach about pKa's and activities, but it could also be used to help students explore the nature of scientific knowledge. We like to believe that science is self-correcting, but is it? 

Evaluation Results

I have not used this in teaching yet and don't have any evaluation results.

Creative Commons License
Attribution, Non-Commercial, Share Alike CC BY-NC-SA
Joanne Stewart / Hope College

Jan 2023: The pKa of water saga continues. The editor-in-chief of JACS agreed to do an ACS video about it with the folks who have been working to correct the wrong value. It's quite interesting! It's on the ACS Youtube website:

Thu, 01/19/2023 - 14:28 Permalink