Chapter 19, Problem 19.134P

Interpretation Introduction

Interpretation:

The pH required to precipitate maximum amount of $HgS$ has to be calculated.

Concept Introduction:

The expression of $K_{sp}$ is the product of the soluble ion expressed in molarity, raised to their coefficients from the balanced dissociation equation.

For a reaction, expression for $K_{sp}$ is,

$\begin{array}{l}{A}_a{B}_b{}_{\left(s\right)}\rightleftharpoons a{A}^{+}{}_{\left(aq\right)}+b{B}^{-}{}_{\left(aq\right)}\\ \\ K_{sp}={\left[A^{+}\right]}^a{\left[B^{-}\right]}^b\end{array}$

Equilibrium constant $K_a$ is given by, $K_a=\frac{\left[H^{+}\right]\left[A^{-}\right]}{\left[HA\right]}$

The pH is the unit of measurment for determining the acidity or alkalinity of a solution. The mathematical definition of pH is the negative logarithm of the molar hydrogen ion concentration.

$pH=-\log \left[H_3{O}^{+}\right]$