Taking into account the definition of pH and pOH, the pH of a 0.059 M solution of Ca(OH)₂ is 13.072.
First of all, pH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance.
The pH is defined as the negative base 10 logarithm of the activity of hydrogen ions, that is, the concentration of hydrogen ions or H₃O⁺:
pH= - log [H⁺]= - log [H₃O⁺]
Similarly, pOH is a measure of hydroxyl ions in a solution and is expressed as the logarithm of the concentration of OH⁻ ions, with the sign changed:
pOH= - log [OH⁻]
The following relationship can be established between pH and pOH:
pOH + pH= 14
In this case, you know that a 0.059 M solution of Ca(OH)₂.
A Strong Base is that base that in an aqueous solution dissociates completely. Ca(OH)₂ is a strong base that dissociates into Ca⁺ ions and OH⁻ ions.
For each mole of calcium hydroxide, 2 OH⁻ ions are obtained, so the molar concentration of OH- ions will therefore be: 0.059 M x 2 = 0.118 M.
For this concentration, the pOH is calculated as:
pOH= - log (0.118 M)
pOH= 0.928
Then, pH can be calculated as:
pH + 0.928= 14
pH= 14 - 0.928
pH= 13.072
Then, the pH of a 0.059 M solution of Ca(OH)₂ is 13.072.
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