Answer:
The pH of a solution in which the concentration of hydroxide ions is 6.9 x 10^-10 M is approximately 4.84.
Step-by-step explanation:
The pH of a solution can be calculated from the concentration of hydroxide ions (OH-) using the relationship between pH, pOH, and the ion product constant for water (Kw). The pOH of a solution is defined as the negative logarithm (base 10) of the hydroxide ion concentration: pOH = -log[OH-]. The pH and pOH of a solution are related by the equation pH + pOH = 14. The ion product constant for water at 25°C is Kw = [H+][OH-] = 1.0 x 10^-14.
In this case, the concentration of hydroxide ions is given as [OH-] = 6.9 x 10^-10 M. We can use this value to calculate the pOH of the solution:
pOH = -log[OH-] = -log(6.9 x 10^-10) = 9.16
Then, we can use the relationship between pH and pOH to calculate the pH of the solution:
pH + pOH = 14
pH + 9.16 = 14
pH = 14 - 9.16
pH = 4.84
Therefore, the pH of a solution in which the concentration of hydroxide ions is 6.9 x 10^-10 M is approximately 4.84.