Question

Instructor Pre-Lab Study Questions 1. How is the pH of a solution related to the [Horr 2. Using the equation for k, explain how (OH) changes when more H,0" is added. 3. Is a solution with a pH of 12.0 acidic or basic? 4. Is a solution with a phl of 2.0 acidic or basic? 5. What is a buffer? 6. If you add acid or base to water, how will the pH change? 7. If you add acid or base to a buffer, how will the pH change?

Answer 1

1. pH is the negative logarithm of H₃O⁺ concentration.

pH = -log[H₃O⁺​​​​​​]

So, the pH of the solution decreases as the concentration of H₃O⁺ increases.

2. K_w = [H₃O⁺][OH^-] = 1.00×10^-14. So, when more of H₃O⁺ is added, the concentration of OH^- will be decreased.

3. A solution is acidic if pH < 7 and basic if pH > 7. So, the solution is basic (pH = 12 > 7)

4. pH = 2.0 < 7. So, the solution is acidic.

5. A buffer is a solution which has the capacity to resist any change in pH when a small amount of acid or base is added to it.

6. When acid is added to water, the solution will become acidic and hence, the pH of the solution will start decreasing.

7. When acid is added to buffer, the pH of the solution will not change since a buffer has the ability to resist change in pH when an acid or base is added to it.