Calculate the concentration of an aqueous solution of Ca1OH22 that has a pH of 10.05.

Verified step by step guidance

1. Identify the relationship between pH and pOH: \( \text{pH} + \text{pOH} = 14 \).
2. Calculate the pOH of the solution using the given pH: \( \text{pOH} = 14 - \text{pH} \).
3. Determine the hydroxide ion concentration \([\text{OH}^-]\) using the formula: \([\text{OH}^-] = 10^{-\text{pOH}}\).
4. Recognize that \( \text{Ca(OH)}_2 \) dissociates in water to produce one \( \text{Ca}^{2+} \) ion and two \( \text{OH}^- \) ions per formula unit.
5. Calculate the concentration of \( \text{Ca(OH)}_2 \) by dividing the \([\text{OH}^-]\) concentration by 2, since each mole of \( \text{Ca(OH)}_2 \) produces two moles of \( \text{OH}^- \).

Key Concepts

pH and pOH

pH is a measure of the acidity or basicity of a solution, defined as the negative logarithm of the hydrogen ion concentration. A pH of 7 is neutral, while values below 7 indicate acidity and above 7 indicate basicity. The relationship between pH and pOH is given by the equation pH + pOH = 14, allowing us to calculate pOH from pH and vice versa.

Hydroxide Ion Concentration

In basic solutions, the concentration of hydroxide ions (OH-) can be derived from the pOH. The pOH is calculated as 14 - pH. Once the pOH is known, the hydroxide ion concentration can be found using the formula [OH-] = 10^(-pOH). This concentration is crucial for determining the concentration of the base in the solution.

Stoichiometry of Calcium Hydroxide

Calcium hydroxide, Ca(OH)2, dissociates in water to produce one calcium ion (Ca2+) and two hydroxide ions (OH-). The stoichiometry of this dissociation is important for calculating the concentration of the original compound based on the hydroxide ion concentration. If the concentration of OH- is known, the concentration of Ca(OH)2 can be determined by dividing the hydroxide concentration by 2.