Chapter 16, Problem 28A

Interpretation Introduction

Interpretation:

The number of decimal places in the pH term needs to be calculated.

Concept Introduction:

The acidity or alkalinity of a solution is expressed by determining pH of the solution. The pH of a solution is defined as negative logarithm of the concentration of ${\text{H}}^{+}$ ion in the solution. pH is expressed as-

  $\text{pH}=-log[H^{+}]$

Answer to Problem 28A

Because the provided concentration term has three significant figures, the value after log should have three significant figures. So, pH of this solution 5.63.

Explanation of Solution

Given Information: ${\text{[H}}^{+}]=2.33\times {10}^{-6}\text{M}$

Calculation:

Concentration of ${\text{H}}^{+}$ ion in the solution is given $2.33\times {10}^{-6}\text{M}$

The given number is 2.33 which contain 3 significant figures. pH value can be calculated as follows:

  $\begin{array}{l}\text{pH}=-log[H^{+}]\\ =-log[2.33\times 10^{-6}]\\ =5.633\end{array}$

Because the provided concentration term has three significant figures, the value after log should have three significant figures. So, pH of this solution 5.63.