Chapter 16, Problem 16.99QP

Interpretation Introduction

Interpretation:

The pH of a solution of ${\text{CO}}_{\text{2}}$ at ${\text{38}}^{\circ }\text{C}$ in equilibrium has to be calculated

Concept Information:

Acid ionization constant ${\text{K}}_{\text{a}}$:

Acids ionize in water. Strong acids ionize completely whereas weak acids ionize to some limited extent.

The degree to which a weak acid ionizes depends on the concentration of the acid and the equilibrium constant for the ionization.

The ionization of a weak acid $\text{HA}$ can be given as follows,

  ${\text{HA}}_{(aq)}\stackrel{}{\to }{\text{H}}^{+}{}_{(aq)}+{\text{A}}^{\text{-}}{}_{(aq)}$

The equilibrium expression for the above reaction is given below.

  $K_a=\frac{[{\text{H}}^{\text{+}}{\text{][A}}^{\text{-}}\text{]}}{[\text{HA]}}$

Where,

  $K_a$ is acid ionization constant,

  $[{\text{H}}^{\text{+}}\text{]}$ is concentration of hydrogen ion

  $[{\text{A}}^{\text{-}}\text{]}$ is concentration of acid anion

  $[\text{HA]}$ is concentration of the acid

pH definition:

The $\text{pH}$ of a solution is defined as the negative base-10 logarithm of the hydrogen or hydronium ion concentration.

  $\text{pH}\text{=}{\text{-log[H}}_{\text{3}}{\text{O}}^{\text{+}}\text{]}$

To Calculate: The pH of a solution of ${\text{CO}}_{\text{2}}$ at ${\text{38}}^{\circ }\text{C}$ in equilibrium