A potassium hydroxide solution has a pH of 12.90. Enough cid is added to react with half of the OH- ions present. What is the pH of the resulting solution? Assume that the products of the neutralization have no effect on pH and that the amount of additional water produced is negligible.

Convert pH 12.90 to H^+.

OH^- are added to neutralize half of that so divide oringial H^+ by 2.
Convert the resulting H^+ to pH.

13.2

To solve this problem, we need to understand that when an acid reacts with a base in a neutralization reaction, the result is the formation of water and a salt. In this case, adding an acid to the potassium hydroxide solution will react with half of the hydroxide ions.

Since we know the pH of the original potassium hydroxide solution is 12.90, we can determine the pOH of the solution using the equation:

pOH = 14 - pH

pOH = 14 - 12.90
pOH = 1.10

Next, we know that pOH and pH are related by the equation:

pOH + pH = 14

Therefore, we can determine the new pH of the resulting solution by subtracting the pOH value we calculated:

pH = 14 - pOH
pH = 14 - 1.10
pH = 12.90

So, the pH of the resulting solution after adding the acid to react with half of the hydroxide ions is 12.90, which remains the same as the original pH of the potassium hydroxide solution.

To find the pH of the resulting solution after the reaction with an acid, we need to understand the concept of neutralization and the relationship between the concentration of OH- ions and the concentration of H+ ions.

1. Neutralization:
Neutralization is a chemical reaction between an acid and a base that results in the formation of water and a salt. In this case, the potassium hydroxide (KOH) solution is a strong base, and the acid being added will neutralize half of the OH- ions present.

2. pH and Concentration of H+ ions:
pH is a measure of the acidity or alkalinity of a solution and is determined by the concentration of H+ ions. The more H+ ions in a solution, the lower the pH. To calculate the pH of a solution, we can use the equation: pH = -log[H+].

Now let's break down the steps to find the pH of the resulting solution:

Step 1: Identify the OH- concentration:
Given that the initial KOH solution has a pH of 12.90, we can find the concentration of OH- ions using the equation: pOH = 14 - pH. Therefore, the pOH is 14 - 12.90 = 1.10. To convert pOH to OH- concentration, we can use the equation: [OH-] = 10^(-pOH). Thus, [OH-] = 10^(-1.10).

Step 2: Reaction with the Acid:
Since we want to react half the OH- ions, the new concentration of OH- ions would be [OH-]/2 = 10^(-1.10)/2.

Step 3: Determine the Concentration of H+ ions:
Since the reaction is neutral, the number of moles of H+ ions formed will be the same as the OH- ions reacted. Therefore, the concentration of H+ ions is equal to the concentration of OH- ions reacted: [H+] = 10^(-1.10)/2.

Step 4: Calculate the new pH:
Using the equation: pH = -log[H+], we can find the pH of the resulting solution by substituting the value for [H+]. Thus, pH = -log(10^(-1.10)/2).

After following these steps and calculating the value, the resulting pH of the solution will be determined.