Chapter 16.2, Problem 4RQ

(a)

Interpretation Introduction

Interpretation: The $pOH$ of the solution needs to be determined.

Concept introduction: $pH$ is a measure of the acidity or alkalinity of a solution. The pH scale generally varies from 0 to 14.

The equation for $pH$ is given by,

  $pH=-\text{log[}{H}^{+}]$ where, $\text{[}{H}^{+}]=\text{ concentration of hydrogen ion}\text{.}$

Similarly, $pOH=-\text{log[}O{H}^{-}]$ where, $\text{[}O{H}^{-}]=\text{ concentration of hydroxide ion}\text{.}$

Relation between $pH\text{ and }pOH\text{ is }pH+pOH=14$

Answer to Problem 4RQ

  $pOH$ of the solution is 4.27.

Explanation of Solution

Here concentration of $H^{+}$ is $1.85\times {10}^{-10}\text{ M}$ .

  $\begin{array}{c}pH=-\text{log[}1.85\times {10}^{-10}]\\ =9.73\end{array}$

Therefore,

  $\begin{array}{c}pOH=14-pH\\ =14-9.73\\ =4.27\end{array}$

(b)

Interpretation Introduction

Interpretation: The $pOH$ of the solution needs to be determined.

Concept introduction: $pH$ is measure of the acidity or alkalinity of a solution. The pH scale generally varies from 0 to 14.

The equation for $pH$ is given by,

  $pH=-\text{log[}{H}^{+}]$ where, $\text{[}{H}^{+}]=\text{ concentration of hydrogen ion}\text{.}$

Similarly, $pOH=-\text{log[}O{H}^{-}]$ where, $\text{[}O{H}^{-}]=\text{ concentration of hydroxide ion}\text{.}$

Relation between $pH\text{ and }pOH\text{ is }pH+pOH=14$

Answer to Problem 4RQ

  $pOH$ of the solution is 9.97.

Explanation of Solution

Here concentration of $H^{+}$ is $9.23\times {10}^{-5}\text{ M}$ .

  $\begin{array}{c}pH=-\text{log[9}\text{.23}\times {\text{10}}^{-5}]\\ =4.03\end{array}$

Therefore,

  $\begin{array}{c}pOH=14-pH\\ =14-4.03\\ =9.97\end{array}$