Question

Which one of the following is not a buffer solution?

• A. $0.8 M\, H _{2} S +0.8\, M\, KHS$
• B. $2 M \,C _{6} H _{5} NH _{2}+2 M C _{6} H _{5} NH _{3}{ }^{+} Br ^{-}$
• C. $3 M H _{2} CO _{3}+3\, M \,KHCO _{3}$
• D. $0.05 \,M\, KClO _{4}+0.05\, M\, HClO _{4}$

Answer 1

Answer: (D)

$0.05 \,M\, KClO _{4}+0.05\, M\, HClO _{4}$

Answer 2

Buffer solutions can be obtained by mixing a weak acid with its salt formed with a strong base or by mixing a weak base with its salt formed with a strong acid. As $HClO _{4}$ is a strong acid, therefore equimolar mixture of $HClO _{4}$ and its salt $KClO _{4}$ is not a buffer solution.