what is the molarity of a solution of the strong base Ca(OH)2 in a solution that has a pH of 10.80?
Ca(OH)2 ==> Ca^2+ + 2OH^-
pH = -log(H^+). Solve for H^+.
Convert to OH^-. 1/2 that will be (Ca^2+) = [Ca(OH)2]
To find the molarity of the strong base Ca(OH)2 in a solution with a pH of 10.80, we need to determine the concentration of hydroxide ions (OH-) in the solution.
Step 1: Use the pH value to find the concentration of hydrogen ions (H+).
pH is defined as the negative logarithm (base 10) of the hydrogen ion concentration. Therefore, we can use the equation:
pH = -log[H+]
Rearranging the equation to solve for [H+]:
[H+] = 10^(-pH)
[H+] = 10^(-10.8)
[H+] ≈ 1.58 x 10^(-11) moles per liter (M)
Step 2: Since calcium hydroxide (Ca(OH)2) is a strong base, it will dissociate completely in water to form two moles of OH- ions for every mole of Ca(OH)2.
Therefore, the concentration of OH- ions is twice the concentration of Ca(OH)2.
[OH-] ≈ 2 × [H+]
[OH-] ≈ 2 × 1.58 x 10^(-11)
[OH-] ≈ 3.16 x 10^(-11) moles per liter (M)
So, the molarity of the Ca(OH)2 solution is approximately 3.16 x 10^(-11) M (moles per liter).
To determine the molarity of a solution of Ca(OH)2 with a pH of 10.80, we need to understand how the pH and pOH values are related.
The pH scale represents the concentration of hydrogen ions (H+) in a solution, and the pOH scale represents the concentration of hydroxide ions (OH-) in a solution. The two scales are complementary and related to each other by the equation:
pH + pOH = 14
Since we have the pH value, we can calculate the pOH value by subtracting the pH from 14:
pOH = 14 - 10.80
pOH = 3.20
Now, let's focus on the hydroxide ions (OH-) because we are dealing with a strong base, Ca(OH)2. The hydroxide ions are the components responsible for its basicity.
The pOH scale is also connected to the concentration of hydroxide ions by the equation:
pOH = -log[OH-]
To find the concentration of OH-, we need to take the antilog of the pOH value:
[OH-] = 10^(-pOH)
[OH-] = 10^(-3.20)
Now that we know the concentration of hydroxide ions, we can find the molarity of the Ca(OH)2 solution.
Ca(OH)2 is a strong base that dissociates completely in water to release two hydroxide ions (OH-) for every molecule:
Ca(OH)2 --> Ca 2+ + 2OH-
Since we have the concentration of OH-, we need to divide it by 2 to get the concentration of Ca(OH)2:
Molarity of Ca(OH)2 = [OH-] / 2
Now, you can plug in the value we calculated for [OH-] earlier:
Molarity of Ca(OH)2 = 10^(-3.20) / 2
Using a calculator, you can evaluate the expression and find the molarity of the Ca(OH)2 solution.