**Correct Option: D. W is the most acidic solution** ### Explanation of the Correct Answer To determine which solution is the most acidic, we need to understand the pH scale. The pH scale ranges from 0 to 14, where: - A pH less than 7 indicates an acidic solution. - A pH of 7 is neutral (pure water). - A pH greater than 7 indicates a basic (alkaline) solution. Given the pH values of the solutions: - W: pH 4 - X: pH 6 - Y: pH 8 - Z: pH 10 **Step 1: Identify Acidic Solutions** From the pH values: - W (pH 4) is acidic. - X (pH 6) is also acidic, but less so than W. - Y (pH 8) is neutral to slightly basic. - Z (pH 10) is basic. Thus, the only solutions that are acidic are W and X. **Step 2: Determine Which is More Acidic** To determine which of the acidic solutions is more acidic, we compare their pH values: - W has a pH of 4. - X has a pH of 6. Since lower pH values indicate stronger acidity, W (pH 4) is more acidic than X (pH 6). Therefore, W is indeed the most acidic solution. ### Explanation of Incorrect Options **Option A: None of these solutions is acidic** - This option is incorrect because both W (pH 4) and X (pH 6) are acidic solutions. Therefore, it is false to say that none of the solutions is acidic. **Option B: The pH of Y is made more acidic by addition of distilled water** - This option is misleading. Adding distilled water (which has a neutral pH of 7) to Y (pH 8) would dilute the solution, but it would not make it more acidic. Instead, the pH would move closer to 7, making it less acidic. Therefore, this statement is incorrect. **Option C: Z is the most acidic solution** - This option is incorrect because Z has a pH of 10, which is basic, not acidic. The most acidic solution is W (pH 4), not Z. ### Summary of Key Points - The pH scale indicates acidity (pH < 7) and basicity (pH > 7). - W (pH 4) is the most acidic solution among the given options. - Adding distilled water to a solution does not increase its acidity; it typically lowers the concentration of hydrogen ions, moving the pH closer to neutral. - Z (pH 10) is basic, not acidic, and therefore cannot be the most acidic solution. ### Revision Summary - pH < 7 indicates acidity; pH > 7 indicates basicity. - W (pH 4) is the most acidic solution. - Adding distilled water to an acidic solution does not make it more acidic. - Z (pH 10) is basic and cannot be the most acidic solution.