Final answer:
To select the correct indicator for a titration, match the indicator's pH range with the titration's equivalence point pH. Bromphenol blue is suitable for strong acid-weak base titrations, not strong acid-strong base titrations. For water quality, pH testing is crucial in identifying contamination.
Step-by-step explanation:
When choosing indicators for titrations, the key is matching the indicator's pH range with the pH at the equivalence point of a particular titration. Each type of titration, whether it's between a strong acid and a strong base, a strong acid and a weak base, or a weak acid and a strong base, has a different pH at its equivalence point, and thus requires a different indicator. For example, bromphenol blue is not ideal for a strong acid-strong base titration because at the equivalence point, the pH is 7, while bromphenol blue changes color around a pH of 3 to 4. Therefore, it's better suited for a strong acid-weak base titration, where the expected pH is lower. An indicator's pKin, or the pH at which it changes color, should be within one unit of the pH at the titration's equivalence point for accurate results.
Regarding water quality, different methods such as observing clarity, testing pH, and filtering can be used to assess contamination. The sources of water pollutants are either point source or non-point source pollution, and human activities significantly affect water quality. Understanding the pH of water samples is a vital part of monitoring water quality, as it can indicate the presence of pollutants.