The definition for Bronsted-Lowry acids and bases state that acids are proton donors and bases are proton acceptors. This is different to the definition of Lewid bases/acids.
The pH scale is a logarithmic scale of the concentration of H+ ions. Strong acids dissociate completely whereas weak acids only partially dissociates in solution.
pH Curves show the relationship of pH against the volume of base/acid added during a titration. At equilavence where the colour change occurs, the pH curve has a sharp vertical rise.
A buffer solution maintains an approximately constant pH, despite dilution or addition of small amount of acid or base. For example, when a small amount of acid is added to an acidic buffer, [H+] increases and hence excess H+ and A- are combined and the equilibrium shifts left, this causes [H+] to decrease close to the original value.