What is the approximate pH of a 0.001 M KOH solution?

To determine the pH of a 0.001 M KOH solution, it is important to recognize that KOH is a strong base and dissociates completely in solution to give hydroxide ions (OH⁻).

First, calculate the concentration of hydroxide ions in the solution. Since KOH dissociates fully, the concentration of OH⁻ ions is also 0.001 M. Next, we can determine the pOH of the solution by using the formula:

pOH = -log[OH⁻]

Substituting the value:

pOH = -log(0.001) = 3

Now, to find the pH from the pOH, we use the relationship:

pH + pOH = 14

By rearranging this equation, we can calculate the pH:

pH = 14 - pOH = 14 - 3 = 11

Thus, the approximate pH of a 0.001 M KOH solution is 11, reflecting its nature as a basic solution due to the presence of hydroxide ions. The higher the pH value, the more basic the solution is, which corresponds to the significant concentration of hydroxide ions derived from the KOH