Chapter 16.2, Problem 16.1CYU

Interpretation Introduction

Interpretation:

The hydronium ion and hydroxide ion concentration in $4\times {10}^{-3}\text{M}\text{HCl}\left(\text{aq}\right)$ at $25{}^{°}\text{C}$ has to be calculated.

Concept Introduction:

In pure water, equilibrium exists between water and the hydronium and hydroxide ions.

    ${\text{2H}}_{\text{2}}\text{O}\left(\text{l}\right)\rightleftharpoons {\text{H}}_{\text{3}}{\text{O}}^{+}\left(\text{aq}\right)+{\text{OH}}^{-}\left(\text{aq}\right)$

The Equilibrium constant $\left({\text{K}}_{\text{w}}\right)$ expression for auto ionization of pure water is:

${\text{K}}_{\text{w}}=\left[{\text{H}}_{\text{3}}{\text{O}}^{+}\right]\left[{\text{OH}}^{-}\right]$        (1)

The value of equilibrium constant is temperature dependent. The ionization constant for pure water is:

${\text{K}}_{\text{w}}=1\times {10}^{-14}$ at $25{}^{°}\text{C}$.