Chapter 15, Problem 15.151MP

Interpretation:

The concentration of $\left[H_3{O}^{+}\right]$ present in the solutionshould be determined

Interpretation Introduction

Concept introduction:

• $pH$ is defined as the negative logarithm of the hydrogen ion of the solution
    $pH=-\log \left[H_3{O}^{+}\right]$
• Strong acid dissociate completely in solution and therefore, the molar concentration of $H^{+}$ ion in the solution is same as that of the acid itself.But the weak acid are not completely dissociated and the relative strength of the weak acid can be compared in terms of their dissociation or ionization constant.The dissociation equilibrium of an acid HA, may be represented as
  $H{A}_{\left(aq\right)}+H_2{O}_{\left(l\right)}\rightleftharpoons H_3{O}^{+}{}_{\left(aq\right)}+A^{-}{}_{\left(aq\right)}$

  Applying law of equilibrium
  
  $K=\frac{\left[H_3{O}^{+}\right]\left[A^{-}\right]}{\left[HA\right]\left[H_{2}O\right]}$

  Since water is present in a large quantity its concentration remains practically constant, the concentration of water may be combined with K to give another constant $K_a$.
  
  $\begin{array}{l}K\left[H_{2}O\right]=\frac{\left[H_3{O}^{+}\right]\left[A^{-}\right]}{\left[HA\right]}\\ K_a=\frac{\left[H_3{O}^{+}\right]\left[A^{-}\right]}{\left[HA\right]}\end{array}$

  Where $K_a$ is the dissociation constant

• The number of moles can be calculated using the relation
  $Numberofmoles=\frac{Concentration\left(Molarity\right)}{Volume}$
• Molar mass of a susbstance is calculated by adding the molar mass of individual element
• Number of moles can also be calculated as
  $Numberofmoles=\frac{Givenmass}{Molarmass}$