Acidic buffer ⇒ weak acid + salt with strong base. An acidic buffer contains weak acid and its salt with a strong base. HClO4 and NaClO4 contains strong acid HClO4 and its salt with strong base NaOH.HClO4 and NaClO4 are not an acidic buffer because strong acid with its salt cannot form buffer solution. So, HClO4 and NaClO, cannot form acidic buffer.