To make a buffer solution you need two things: 1) a weak acid (or base) and 2) the presence of the conjugate base of that weak acid. So for example we could make a buffer with HF and NaF since HF is a weak acid and NaF would completely dissociate into Na+ and F-. The F- is the conjugate base of the weak acid HF.
Now, it so happens that HClO3 (chloric acid) is a strong acid. It is a strong acid because it completely dissociates into H+ and ClO3- ions in water. Since HClO3 is a strong acid there is no equilibrium (at least no appreciable equilibrium)--the reaction goes only one way, to the right. To have a buffer solution we really need to have an equilibrium environment (common ion effect) and we don't have that in this case.
So, since HClO3 is a strong acid we will not produce a buffer solution.
I hope that helps.
Ask if you have any questions or need any clarifications and I'll be happy to do what I can.