Chapter 9, Problem 9.3P

Interpretation Introduction

Interpretation:

For a below reaction $\text{pH}$ of solution has to be calculated.

  ${\text{H}}_{\text{2}}{\text{C=CHCO}}_{\text{2}}\text{H}\rightleftharpoons {\text{H}}_{\text{2}}{\text{C=CHCO}}_{\text{2}}^{-}+{\text{H}}^{+}$

Concept Introduction:

The equation for buffer is described by Henderson-Hasselbach equation and it is a rearranged for equilibrium constant, $K_{\text{a}}$. Consider an equation of dissociation of an acid as follows:

  $\text{HA}\rightleftharpoons {\text{H}}^{+}+{\text{A}}^{-}$

Formula to calculate $\text{pH}$ is as follows:

  $\text{pH}=p{K}_{\text{a}}+\log \left(\frac{\left[{\text{A}}^{-}\right]}{\left[\text{HA}\right]}\right)$

Here,

$p{K}_{\text{a}}$ is acid dissociation constant of weak acid $\text{HA}$.

$\left[{\text{A}}^{-}\right]$ is concentration of conjugate base ${\text{A}}^{-}$

$\left[\text{HA}\right]$ is concentration of acid $\text{HA}$.