What is the pH of a 0.05 M solution of potassium hydroxide??
To determine the pH of a solution, you need to know the concentration of a strong base like potassium hydroxide (KOH). You can calculate the pH using the following steps:
Step 1: Write the balanced chemical equation for the dissociation of KOH:
KOH → K+ + OH-
Step 2: Determine the concentration of hydroxide ions (OH-) in the given solution. Since KOH is a strong base, it fully dissociates in water, so the concentration of OH- will be equal to the concentration of KOH.
Given the concentration of the solution is 0.05 M, the concentration of OH- is also 0.05 M.
Step 3: Use the equation for the hydroxide ion concentration to calculate pOH:
pOH = -log[OH-]
Taking the negative logarithm of the concentration, we get:
pOH = -log(0.05)
Step 4: Calculate the pH using the pOH value:
pH + pOH = 14
Rearranging the equation to solve for pH:
pH = 14 - pOH
Plugging in the pOH value from Step 3:
pH = 14 - (-log(0.05))
Simplifying:
pH = 14 - (-(-1.301))
Calculating the terms inside the parentheses:
pH = 14 - 1.301
Finally, solving for pH:
pH ≈ 12.699
Therefore, the pH of a 0.05 M solution of potassium hydroxide is approximately 12.699.