Would a weak acid completely ionize in water ionize at a high pH ionize at a pH of 7 n act as part of a buffer

Answer 1

If an acid completely ionizes in water, it would not be called a weak acid, right?
A weak acid can completely ionize at a high pH. Remember: H3O+ concentration is very low at a high pH. This very low H3O+ concentration would not prohibit a weak acid from (almost) complete ionization, which is determined by Ka = [H3O+]*[A-] /[HA]
When an acid got completely ionized, it lost its buffering capability, since a buffer solution must have sufficient [A-] and [HA] concentrations, such that the system may be able to conpensate by either reducing or increasing the concentration of [A-] at the cost of [HA].