Q19.41P - Chemistry: Molecular Nature Of Matter And Change

Question

Why doesn’t the addition of an acid-base indicator affect the pH of the test solution?

Step-by-Step Solution

Answer

Because of an indicator's properties, only a small amount is added to a solution, small enough to have no effect on the pH. Thus the addition of an acid-base indicator does not affect the pH of a test solution.

Step 1: Define indicators

A material that can be added to a reaction mixture to show a titration's equivalence point is known as an indicator. A pH is frequently measured with coloured indicators. In a basic environment, these indications are different in colour than in an acidic environment.

Step 2: Explanation

Weak acids are used as acid-base indicators. They have bright colors, which is appropriate for an indicator, and they react to small changes in a pH by changing color within their prescribed pH range. Because of an indicator's properties, only a small amount is added to a solution, small enough to have no effect on the pH.