If the pH of a Ca(OH)2 solution is measured as 9.0, what is the concentration of the Ca(OH)2 solution?
A. 1 * 10^-5 M
B. 1 * 10^-8 M
C. 1 * 10^-9 M
D. 1 * 10^-6 M
I really have no clue
pH=-log(H)
H=10^-9
but OH*H=10^-14
OH=10^-5
Thank you!!!
To determine the concentration of a Ca(OH)2 solution based on its pH, we need to understand the relationship between pH and concentration. pH is a measure of the hydrogen ion concentration in a solution and is defined as the negative logarithm (base 10) of the hydrogen ion concentration.
The equation that relates pH and concentration for a strong base, like Ca(OH)2, is:
pOH = -log(OH-)
Since Ca(OH)2 dissociates into two OH- ions, the concentration of OH- ions is twice the concentration of Ca(OH)2. Therefore, the equation becomes:
pOH = -log(2 * concentration of Ca(OH)2)
Given that the pH of the Ca(OH)2 solution is 9.0, we can use the fact that pH + pOH = 14 to find the pOH value:
pOH = 14 - 9 = 5
Now, we can solve for the concentration of Ca(OH)2 using the equation:
5 = -log(2 * concentration of Ca(OH)2)
Rearranging the equation, we get:
10^-5 = 2 * concentration of Ca(OH)2
Finally, dividing both sides by 2 gives us the concentration of Ca(OH)2:
concentration of Ca(OH)2 = 10^-5 / 2 = 5 * 10^-6 M
Therefore, the correct answer is option D. 1 * 10^-6 M.