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

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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} \(\text{ M}\).

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

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.