Chapter 16, Problem 16.72QP

Interpretation Introduction

Interpretation:

In a certain experiment, a student finds that the pH values of 0.10-M solutions of three potassium salts KX, KY, and KZ are 7.0, 9.0, and 11.0, respectively. The acids HX, HY, and HZ has to be arranged in order of increasing acid strength.

Concept Information:

When a Bronsted acid donates a proton, what remains of the acid is known as a conjugate base; when a Bronsted base accepts a proton, the newly formed protonated species is known as a conjugate acid.  This can be given by the below equation as shown in Figure 1.

Figure 1

The strength of acid can be determined based on,

• The bond strength – (acid strength increases as bond strength decreases)
• The bond polarity – (acid strength increases as degree of polarity increases)
• The pH of the acid – (acid strength increases as the pH of acid decreases)

pH scale:

The acidity or basicity of an aqueous solution was calculated using a numerical scale called pH scale.

Based on pH of the solution, salt solutions can be classified as

• Acidic        -    (pH will be less than seven)
• Basic         -    (pH will be more than seven)
• Neutral     -    (pH will be equal to seven)

The pH scale expresses the acidity of aqueous solutions.  The greater the pH, the weaker the acid will be.

To Arrange: The acids HX, HY and HZ in order of increasing acid strength.