Are #"magnesium phosphate/magnesium bromide"#, #"sulfuric acid/sodium bisulfate"# #"buffer solutions"#?

1 Answer
Jan 30, 2016

#MgBr_2"/"MgHPO_4; H_2SO_4"/"NaHSO_4# are NOT buffer systems.

Explanation:

A buffer solution is composed of a weak acid and its conjugate base in APPRECIABLE concentrations, which acts to keep #pH# close to the #pK_a# of the weak acid, and resist gross changes in #pH#. Both sulfuric acid and sodium bisulfate are strong acids in water, and thus do not fall under the umbrella of the given definition.

The #pK_a# of lactic acid would be similar to that of acetic acid (says he, without bothering to look up the #pK_a# of lactic acid; it would be reasonably close to #4.76#), and hence this system COULD act as a buffer.

All of this presupposes AQUEOUS solution.