How buffers respond to strong acids and bases, and why Ka differs experimentally

[dagg3r]

hi guys need some help with buffers heh

anyways my query is say i have a buffer system, then i add say a strong base or a strong acid, then the ph changes, what's a general statement i can make for these observations regarding the h+ ion concentration and stuff. I know that if i have the buffer, and i add hcl the h+ ions will be consumed by the conjugate base in the buffer and if we add heaps of acid the ph will decrease cos of too much h+ just an opinion anyone care to help me out :)

and anyone also care to give me reasons and differences why ka value experimentally is different to the literally value? when doing a titration of Nh3 against HCl. thanks

i posted here since i realize this would be most appropriate as it is the chemistry forun :)

 

[Borek]

First of all, look for Henderson-Hasselbach equation - it describes buffers, it should be also be of interest for you how to get to HH equation from the dissociation constant definition.

As for sources of differences: ionic strength of solution, temperature, accuracy of measurements (especially calibration of pH meter).

Chemical calculators for labs and education

BATE - pH calculations, titration curves
CASC - concentration conversions, solution preparation

 

[GCT]

Your text, should show you in steps, how do perform such calculations. If you have any specific questions, feel free to ask them here, and be sure to attempt them first.