What solution is formed when a weak acid is mixed with quantities of its conjugate base?

1 Answer
Mar 21, 2016

Answer:

Formation of a buffer solution is described.

Explanation:

A buffer solution is a mixture of a weak acid and its conjugate base in appreciable concentrations, which acts to resist gross changes in #pH#.

Without deriving the equation:

#pH = pK_a + log_10{[[A^-]]/[[HA]]}#

This tells us that when equal concentrations of ammonia and ammonium chloride are present, #pH = pK_a# because #log_10{1}=0#.

Because #Cl^-# is the conjugate base of a strong acid, it does not compete strongly for the proton, and has no effect on #pH#.