Calculate [H3O+] in each aqueous solution at 25 °C, and classify each solution as acidic or basic. a. [OH-] = 1.1 * 10^-9 M b. [OH-] = 2.9 * 10^-2 M c. [OH-] = 6.9 * 10^-12 M

Name: Chemistry: A Molecular Approach
Author: Tro
ISBN: 9780134112831

Verified step by step guidance

Use the water dissociation constant at 25 °C, which is Kw = 1.0 \(\times\) 10^{-14} \(\text{ M}\)^2, to find [H_3O^+].

For each solution, apply the formula [H_3O^+] = \(\frac{Kw}{[OH^-]}\) to calculate the hydronium ion concentration.

Substitute the given [OH^-] values into the formula: a. [OH^-] = 1.1 \(\times\) 10^{-9} \(\text{ M}\), b. [OH^-] = 2.9 \(\times\) 10^{-2} \(\text{ M}\), c. [OH^-] = 6.9 \(\times\) 10^{-12} \(\text{ M}\).

Determine the nature of each solution: If [H_3O^+] > 1.0 \(\times\) 10^{-7} \(\text{ M}\), the solution is acidic; if [H_3O^+] < 1.0 \(\times\) 10^{-7} \(\text{ M}\), the solution is basic.

Classify each solution based on the calculated [H_3O^+]: a. Compare [H_3O^+] to 1.0 \(\times\) 10^{-7} \(\text{ M}\), b. Compare [H_3O^+] to 1.0 \(\times\) 10^{-7} \(\text{ M}\), c. Compare [H_3O^+] to 1.0 \(\times\) 10^{-7} \(\text{ M}\).

Key Concepts

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

pH and pOH Relationship

The pH and pOH of a solution are related through the equation pH + pOH = 14 at 25 °C. This relationship allows us to determine the acidity or basicity of a solution by calculating one from the other. A pH less than 7 indicates an acidic solution, while a pH greater than 7 indicates a basic solution.

Ion Product of Water

The ion product of water (Kw) is a constant at 25 °C, equal to 1.0 x 10^-14. This means that the product of the concentrations of hydrogen ions [H3O+] and hydroxide ions [OH-] in pure water is always 1.0 x 10^-14. This relationship is crucial for calculating [H3O+] from given [OH-] concentrations.

Acidic and Basic Solutions

A solution is classified as acidic if [H3O+] > [OH-] and basic if [H3O+] < [OH-]. By calculating [H3O+] from the provided [OH-] values using the ion product of water, we can determine the nature of each solution. This classification is essential for understanding the behavior of different solutions in chemical reactions.

Related Practice

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

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Pick the stronger base from each pair. c. F^– or ClO^–

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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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