Respuesta :
ANSWER
The pH of the solution is 12.75
EXPLANATION;
Given that;
The volume of the solution is 2500mL
The mass of calcium hydroxide is 10.4g
Follow the steps below to find pH of the solution
Step 1; Convert the volume to L
Recall, that 1mL is equivalent to 0.001L
Let the volume of the solution be x
[tex]\begin{gathered} \text{ 1mL }\rightarrow\text{ 0.001L} \\ \text{ 2500mL }\rightarrow\text{ xL} \\ \text{ cross multiply} \\ \text{ 1mL }\times\text{ xL }=0.001L\text{ }\times\text{ 2500mL} \\ \text{ isolate x} \\ \text{ x = }\frac{0.001L\times2500\cancel{mL}}{1\cancel{mL}} \\ \text{ x = 0.001 }\times\text{ 2500} \\ \text{ x = 2.5L} \end{gathered}[/tex]Step 2; Find the mole of calcium hydroxide using the formula below
[tex]\text{ mole }=\text{ }\frac{\text{ mass}}{\text{ molar mass}}[/tex]Recall, that the molar mass of calcium hydroxide is 74.093 g/mol
[tex]\begin{gathered} \text{ mole }=\text{ }\frac{\text{ mass}}{\text{ molar mass}} \\ \\ \text{ mole }=\text{ }\frac{\text{ 10.4}}{\text{ 74.093}} \\ \text{ mole = 0.140 mol} \end{gathered}[/tex]Step 3; Find the molarity of calcium hydroxide
[tex]\begin{gathered} \text{ molarity = }\frac{\text{ mole }}{\text{ volume}} \\ \\ \text{ molarity = }\frac{0.140}{2.5} \\ \text{ molarity = 0.056M} \end{gathered}[/tex]Since calcium hydroxide is a base, then calculate the pOH of calcium hydroxide
[tex]\text{ pOH = - log \lbrack OH}^-\text{ \rbrack}[/tex][tex]\begin{gathered} \text{ \lbrack OH}^-\text{ \rbrack = 0.056M} \\ \text{ pOH = -log 0.056} \\ \text{ pOH = 1.25} \end{gathered}[/tex]Step 5; Find the pH of the solution
Recall, that pOH + pH = 14
[tex]\begin{gathered} \text{ pOH }+\text{ pH }=\text{ 14} \\ \text{ 1.25 }+\text{ pH }=\text{ 14} \\ \text{ subtract 1.25 from both sides of the equation} \\ \text{ 1.25 - 1.25 + pH = 14 - 1.25} \\ \text{ pH = 12.75} \end{gathered}[/tex]Therefore, the pH of the solution is 12.75
