Chapter 18, Problem 81A

Interpretation Introduction

Interpretation:

The $pHandpOH$ of the solution is to be found out using given concentration.

Concept introduction:

$pH$ gives the concentration of hydrogen ion in a solution.

$pOH$ gives the concentration of hydrogen ion in a solution.

It tells about acidity and basicity of a solution.

It is given by:

$\begin{array}{l}pH=-\log \left[H^{+}\right]\\ pOH=-\log \left[O{H}^{-}\right]\\ \left[H^{+}\right]isconcentationofhydrogenions\\ \left[O{H}^{-}\right]isconcentationofhydroxylions\end{array}$

Answer to Problem 81A

$\begin{array}{l}pH=2.27\\ pOH=12.73\end{array}$

Explanation of Solution

Given:

$\begin{array}{l}\left[H^{+}\right]=5.40\times {10}^{-3}M\\ \left[O{H}^{-}\right]=1.85\times {10}^{-12}M\end{array}$

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

Therefore,

$\begin{array}{c}pH=-\log (5.4\times {10}^{-3})\\ =-\log 5.4-\log {10}^{-3}\\ =-0.73+3\\ =2.27\\ pOH=-\log (1.85\times {10}^{-13})\\ =-\log 1.85-\log {10}^{-13}\\ =-0.27+13\\ =12.73\end{array}$

Conclusion

Thus,

$\begin{array}{l}pH=2.27\\ pOH=12.73\end{array}$