a solution of oh negative ions is added to a beaker of pure water 25 degrees celcius to a final concentration of 137 nM calculate the ph of the solution
To calculate the pH of the solution, we need to know the concentration of H+ ions. Since we have the concentration of OH- ions, we can use the concept of water self-ionization to find the concentration of H+ ions.
Water can self-ionize into H+ and OH- ions according to the equation:
H2O ⇌ H+ + OH-
At 25 degrees Celsius, the concentration of H+ and OH- ions in pure water is equal, which is 1 x 10^-7 M. This is known as the neutral pH.
Since we have the concentration of OH- ions, we can use this information to find the concentration of H+ ions.
Given:
Concentration of OH- ions = 137 nM = 137 x 10^-9 M
Using the concept of water self-ionization, we know that [H+][OH-] = 1 x 10^-14 M^2.
Let's denote the concentration of H+ ions as x.
Therefore, x * (137 x 10^-9) = 1 x 10^-14
Simplifying this equation, we can solve for x:
x = (1 x 10^-14) / (137 x 10^-9)
x ≈ 7.2993 x 10^-20 M
Now that we have the concentration of H+ ions, we can calculate the pH using the equation:
pH = -log[H+]
pH = -log(7.2993 x 10^-20)
pH ≈ 19.14 (rounded to two decimal places)
So, the pH of the solution is approximately 19.14.