Chapter 16, Problem 49A

Interpretation Introduction

Interpretation:

The combination which can act as buffer is to examine.

Concept introduction:

A solution is buffer which resists the change in $\mathrm{p}\mathrm{H}$ value when a small amount of acid or base is added to it.

Buffer solution is of two types:

• Acidic buffer
• Basic buffer

The component necessary for buffer solution is

• Weak acid and a salt of weak acid with strong base.
• Weak base and a salt of weak base with strong acid.

Answer to Problem 49A

Options A, C, D

Explanation of Solution

  $\mathrm{H}\mathrm{C}\mathrm{N}-\mathrm{N}\mathrm{a}\mathrm{C}\mathrm{N}$ is acidic buffer because $\mathrm{H}\mathrm{C}\mathrm{N}$ is weak acid and $\mathrm{N}\mathrm{a}\mathrm{C}\mathrm{N}$ is salt of weak acid with strong base $\mathrm{N}\mathrm{a}\mathrm{O}\mathrm{H}$

  $\mathrm{H}\mathrm{F}-\mathrm{K}\mathrm{F}$ is acidic buffer because $\mathrm{H}\mathrm{F}$ is weak acid and $\mathrm{K}\mathrm{F}$ is salt of weak acid with strong base $\mathrm{K}\mathrm{O}\mathrm{H}$

  $\mathrm{H}{\mathrm{C}}_3{\mathrm{H}}_5{\mathrm{O}}_2-\mathrm{N}\mathrm{a}{\mathrm{C}}_3{\mathrm{H}}_5{\mathrm{O}}_2$ is acidic buffer because $\mathrm{H}{\mathrm{C}}_3{\mathrm{H}}_5{\mathrm{O}}_2$ is weak acid and $\mathrm{N}\mathrm{a}{\mathrm{C}}_3{\mathrm{H}}_5{\mathrm{O}}_2$ is salt of weak acid with strong base $\mathrm{N}\mathrm{a}\mathrm{O}\mathrm{H}$

Conclusion

Option B is incorrect because ${\mathrm{H}}_3\mathrm{P}{\mathrm{O}}_4-{\mathrm{K}}_3\mathrm{P}{\mathrm{O}}_4$ is not acidic buffer as ${\mathrm{H}}_3\mathrm{P}{\mathrm{O}}_4$ is strong acid.