Chapter 16, Problem 16.85QP

Interpretation Introduction

Interpretation:

The concentrations of ${\text{HCO}}_{\text{3}}{}^{\text{-}},{\text{CO}}_3{}^{2-}\text{and}{\text{H}}^{\text{+}}$ ions in a 0.025 M ${\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}$ solution 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,

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

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

To Calculate: The concentrations of ${\text{HCO}}_{\text{3}}{}^{\text{-}},{\text{CO}}_3{}^{2-}\text{and}{\text{H}}^{\text{+}}$ ions in a 0.25 M ${\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}$ solution