Which of the following best explains why the pH scale is important in science, along with examples of its scientific applications?

• A. It is used to determine the concentration of solids in a mixture, which is important for material science and engineering.
• B. It helps scientists identify the boiling point of liquids, which is essential in physical chemistry and thermodynamics.
• C. It is primarily used to measure the density of gases, which is important in atmospheric science.
• D. It allows scientists to measure the acidity or basicity of solutions, which is crucial in fields such as biology (e.g., enzyme activity), environmental science (e.g., water quality), and medicine (e.g., blood pH).

Answer: (D)

Verified step by step guidance

1. Understand that the pH scale is a measure of the acidity or basicity of a solution, which is determined by the concentration of hydrogen ions (H\textsuperscript{+}) in that solution.
2. Recall the definition of pH: \(\mathrm{pH} = -\log_{10}[\mathrm{H}^+]\), where \([\mathrm{H}^+]\) is the molar concentration of hydrogen ions.
3. Recognize that measuring pH is important because many chemical and biological processes depend on the acidity or basicity of their environment, affecting reaction rates and molecular stability.
4. Consider examples where pH measurement is crucial: in biology, enzyme activity often depends on pH; in environmental science, pH affects water quality and aquatic life; in medicine, maintaining blood pH within a narrow range is vital for health.
5. Conclude that the pH scale's importance lies in its ability to quantify acidity/basicity, which is essential across multiple scientific disciplines, unlike the other options that relate to different properties such as boiling point, density, or solid concentration.