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Ch.17 - Acids and Bases
Tro - Chemistry: A Molecular Approach 6th Edition
Tro6th EditionChemistry: A Molecular ApproachISBN: 9780137832217Not the one you use?Change textbook
All textbooksTro 6th EditionCh.17 - Acids and BasesProblem 51
Chapter 17, Problem 51

Calculate the pH and pOH of each solution at 25 °C. a. [H3O+] = 1.7 × 10^-8 M b. [H3O+] = 1.0 × 10^-7 M c. [H3O+] = 2.2 × 10^-6 M

Verified step by step guidance
1
Identify the relationship between pH and [H3O+]. The pH is calculated using the formula: \( \text{pH} = -\log[\text{H}_3\text{O}^+] \).
Calculate the pH for each given [H3O+] concentration using the formula from step 1.
Understand the relationship between pH and pOH. At 25 °C, the sum of pH and pOH is always 14: \( \text{pH} + \text{pOH} = 14 \).
Calculate the pOH for each solution using the relationship from step 3: \( \text{pOH} = 14 - \text{pH} \).
Review the calculated pH and pOH values to ensure they are consistent with the properties of acidic and basic solutions. For example, a pH less than 7 indicates an acidic solution, while a pH greater than 7 indicates a basic solution.>

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

pH Scale

The pH scale measures the acidity or basicity of a solution, defined as the negative logarithm of the hydronium ion concentration: pH = -log[H3O+]. A lower pH indicates a more acidic solution, while a higher pH indicates a more basic solution. The scale typically ranges from 0 to 14 at 25 °C, with 7 being neutral.
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pOH Scale

The pOH scale is similar to the pH scale but measures the concentration of hydroxide ions in a solution. It is defined as pOH = -log[OH-]. The relationship between pH and pOH is given by the equation pH + pOH = 14 at 25 °C, allowing for the calculation of one from the other.
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Ion Product of Water

The ion product of water (Kw) is the equilibrium constant for the self-ionization of water, defined as Kw = [H3O+][OH-] = 1.0 × 10^-14 at 25 °C. This relationship is crucial for calculating pH and pOH, as it allows for the determination of hydroxide ion concentration from the hydronium ion concentration and vice versa.
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Related Practice
Textbook Question

Calculate [H3O+] and [OH–] for each solution at 25 °C. a. pH = 8.55

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Textbook Question

Pick the stronger base from each pair. c. NO2– or NO3–

Textbook Question

Rank the solutions in order of decreasing [H3O+]: 0.10 M HCl; 0.10 M HF; 0.10 M HClO; 0.10 M HC6H5O.

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Textbook Question

Calculate [H3O+] and [OH–] for each solution at 25 °C. b. pH = 11.23 c. pH = 2.87

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Textbook Question

Classify each acid as strong or weak. If the acid is weak, write an expression for the acid ionization constant (Ka). d. H2CO3

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Textbook Question

Complete the table. (All solutions are at 25 °C.)

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