Question

I did a LAB today and my theoretical ph values didn't match with the actual ph value.

the LAB was about serial dilution of 0.1M HCl. do you know why...?

Answer 1

This theoretical and practical mismatch occurs in acid base titrations. This is more so because the HCL solutions as well as the NaOH solutions are usually difficult to prepare. This difference is because of the fact that there may be problems in the mixture homogeneity. Such smaller concentration gradient might be very difficult to rule out, since titrations are generally performed by hand mixing and mixing here plays the major role. Moreover, With ph values lower than 4, there is a greater chance that there would be formation of carbonic acid and the concentration of dissolved carbon dioxide would increase. There might also be a chance that the electrode may not be properly calibrated. Also, an electronic mixer could be used for preparing the mixes, in order to avoid such problems.