Why phosphate buffer solution (PBS) at pH 1 and pH 2 are unstable? Which is an appropriate buffer solution to use at acidic medium?
Hydrochloric acid-potassium chloride can be used as a buffer at pH 1-2. You can even buy it from Sigma.
(http://www.sigmaaldrich.com/analytical-chromatography/analytical-products.html?TablePage=8679114)
Dear Kisan: I suggest you look a titration curve of phosphoric acid in an analytical chemistry book.
Phosphoric acid is a strong acid, but not completely dissociated and for example, a 0.1 mol/L solution presents pH ~1.6. So, to have a solution with pH = 1.0, you must work with very high concentration. To have a buffer with pH = 2.0 it is possible to get with some facility.
To calculate these data, I suggest you the program CURTIPOT that you can download from the internet. It is a nice program wrote by my colleague IVANO GUTZ. It is free in the internet. There are the constants of about 200 acids and for phosphoric acid you can look which concentration you need have to make a good buffer (as you know, the best buffer is the one which contains 50% of each of the forms H3PO4/H2PO4-).
Best regards,
Lucio
Thank you Prof. Adam B Shapiro.
Thank you Prof. Lucio Angnes: I downloaded the program CURIPOT and I find it very easy and useful. Thank you :)
You may want to check my post at this related query:
https://www.researchgate.net/post/Why_do_I_struggle_to_adjust_lower_pH_of_my_phosphate_buffer_at_a_certain_pH_point_even_though_I_add_too_much_acidic_solution
- Badges
- Science method