Question

a buffer solution is all of the following except:
a solution that contains both a weak acid and its conjugate base.
a solution that resists a change in ph when a base is added.
a solution that resists a change in ph when an acid is added.
a solution that regulates ph because it is such a strong acid or base.
all of the above are true.

Explanation:

A buffer solution resists pH changes when acid/base is added, typically containing a weak acid and its conjugate base (or weak base and conjugate acid). Strong acids/bases do not form buffers—they cause large pH shifts instead of regulating pH.

Answer:

a solution that regulates pH because it is such a strong acid or base.