Question

Which of the following mixture is not a buffer solution?

• A. 100 ml of 0.5 $N{H}_{4}Cl$ and 100 ml of 0.6 $NN{H}_{4}OH$
• B. 100 ml of 0.6 $N$ $HCN$ and 100 ml of 0.4 $N$ $NaOH$
• C. 100 ml of 0.2 $N$ $N{H}_{4}OH$ and 100 ml of 0.2 $NC{H}_{3}COOH$
• D. 100 ml of 0.4 $N$ $HCl$ and 100 ml of 0.4 $N$ $NaOH$

Answer 1

Answer: (C), (D)

The correct options are
C 100 ml of 0.2 $N$ $N{H}_{4}OH$ and 100 ml of 0.2 $NC{H}_{3}COOH$
D 100 ml of 0.4 $N$ $HCl$ and 100 ml of 0.4 $N$ $NaOH$

An acidic buffer solution is prepared by mixing a weak acid and its salt with a strong base. A basic buffer solution is prepared by mixing a weak base and its salt with strong acid. A buffer solution cannot be obtained by mixing a strong acid with a strong base.

$HCl$ is a strong acid and $NaOH$ is a strong base, therefore it forms salt and not a buffer solution.

$N{H}_{4}OH$ and $C{H}_{3}COOH$ is a mixture of a weak acid and weak base, therefore it forms salt and not buffer solution.

Hence option C & D is correct.