Chapter U4.86, Problem 7E

Interpretation Introduction

Interpretation:

The pH of a 2.5 M HCl solution needs to be calculated.

Concept Introduction:

The acidity of a solution is expressed in terms of its pH which is essentially the measure of the hydrogen ion (H⁺) concentration of that solution. Mathematically,

  $\text{pH = }-{\text{log[H}}^{\text{+}}\text{] -----(1)}$

If the pH is below 7 the solution is termed as acidic, if greater than 7 the solution is basic. A neutral solution will have a pH = 7.

Answer to Problem 7E

pH = -0.40

Explanation of Solution

The concentration of HCl solution is given 2.5 M

Since, HCl is a strong acid, the H+ ion concentration would be 2.5 M

The pH of solution can be calculated as follows:

  $\begin{array}{l}\text{pH = }-{\text{log[H}}^{\text{+}}\text{] }\\ \text{=}-\text{log[2}\text{.5] = }-\text{0}\text{.40}\end{array}$

Conclusion

Thus, the pH of a 2.5 M HCl solution is -0.40.