Buffer?

[akcapr]

Is it possibe to make a buffer with acetic acid and sodium acetate. Also wat r some other ones i cold meke

[MulderMan]

did you want to use the buffer for something specific, or did you just want to make something? theres quite a few buffers that can be made. what about the one thats in your blood (carbonic acid and bicarbonate).

[akcapr]

i just wanted to see one work. Ive tried some before but ive never been able to make them work.

[akcapr]

ya

[akcapr]

would NaCl work as a buffer for HCl?

[jdurg]

Absolutely not. Buffers work based upon the equillibrium of a weak acid/base and their dissociation into anions and cations. Hydrochloric acid dissociates fully into hydrogen ions and chloride ions in solution. Therefore, there is no equillibrium to speak of.

 

With the acetic acid/acetate buffer, when you put acetic acid in solution an equillibrium develops betwen the undissociated acid and the acetate/hydrogen ions. If you add acetate salt to that equillibrium, you alter the concentrations a bit. Adding some acid to the solution will cause some acetic acid to form as the hydrogen ions attach to the acetate ions. Equillibrium will then occur and you'll see that the pH changes either very slightly or not at all. If you add a base to this buffer, it will pull a hydrogen atom off of the acetic acid and form water and the acetate salt. Again, an equillibrium will shift to compensate for the change in acid concentration. Once more the pH will remain constant.

 

With an HCl and NaCl setup, adding an acid will not cause the Cl- ions to reform HCl. The equillibrium does not really exist for that. Adding a base will cause the HCl to form water and the chloride salt. The non-existant equillibrium will not move and there will be no 'buffer' action.