determine the pH of each of the following solutions:

0.0812M HCl pH
3.11*10^-4 M HI pH
8.65*10^-8 M KOH pH
0.00212M Ca(OH)2 pH

To determine the pH of each solution, you need to know the concentration of the acidic or basic solutions and understand the concepts of pH and pOH.

The pH scale measures the acidity or basicity of a solution and ranges from 0 to 14. A pH value below 7 indicates acidity, while a pH value above 7 indicates alkalinity (basicity). Neutral solutions have a pH of 7.

pH is calculated using the formula: pH = -log[H+], where [H+] represents the concentration of hydrogen ions in the solution.

Now let's calculate the pH for each of the given solutions.

1. 0.0812 M HCl:
HCl is a strong acid, which means it completely dissociates in water to form H+ ions. Given that the concentration of HCl is 0.0812 M, the concentration of H+ ions is also 0.0812 M. So, the pH can be calculated as:
pH = -log(0.0812) ≈ 1.09

Therefore, the pH of the 0.0812 M HCl solution is approximately 1.09.

2. 3.11 x 10^-4 M HI:
HI is also a strong acid. Since it completely dissociates in water, the concentration of H+ ions is the same as the concentration of HI, i.e., 3.11 x 10^-4 M. The pH can be calculated as follows:
pH = -log(3.11 x 10^-4) ≈ 3.51

Therefore, the pH of the 3.11 x 10^-4 M HI solution is approximately 3.51.

3. 8.65 x 10^-8 M KOH:
KOH is a strong base. When it dissolves in water, it releases OH- ions. The concentration of OH- ions can be calculated as 8.65 x 10^-8 M. To convert this to the concentration of H+ ions, we can use the equation Kw = [H+][OH-], where Kw represents the ion product of water and has a constant value of 1 x 10^-14 at 25°C. Rearranging this equation, we get [H+] = Kw/[OH-].

[H+] = (1 x 10^-14)/(8.65 x 10^-8) ≈ 1.16 x 10^-7 M
(Note: Since KOH is a strong base, we can assume that [H+] is approximately equal to [OH-])

Therefore, the pH can be calculated as follows:
pH = -log(1.16 x 10^-7) ≈ 6.94

Therefore, the pH of the 8.65 x 10^-8 M KOH solution is approximately 6.94.

4. 0.00212 M Ca(OH)2:
Calcium hydroxide (Ca(OH)2) is a strong base. Similar to the previous case, the concentration of OH- ions can be calculated as 0.00212 M. Using the same relationship as in the previous step, we can calculate:

[H+] = Kw/[OH-] = (1 x 10^-14)/(0.00212) ≈ 4.72 x 10^-12 M

To find the pH, we use the formula:
pH = -log(4.72 x 10^-12) ≈ 11.33

Therefore, the pH of the 0.00212 M Ca(OH)2 solution is approximately 11.33.