What scale is used to measure the acidity or alkalinity of a substance, with 7 being neutral?

The pH scale is specifically designed to measure the acidity or alkalinity of a solution, with values ranging from 0 to 14. A pH of 7 indicates a neutral solution, meaning it is neither acidic nor alkaline. Values below 7 signify increasing acidity, while values above 7 indicate increasing alkalinity. This scale is crucial in various fields, including chemistry, biology, and environmental science, as it helps determine the chemical properties of substances and their behavior in different environments.

The other scales mentioned serve different purposes. The boiling point scale measures the temperature at which a substance transitions from liquid to gas and is not related to acidity or alkalinity. The temperature scale focuses on measuring thermal energy, while the concentration scale pertains to the amount of a substance in a given volume and does not provide information about pH levels. Hence, the pH scale is the only option that accurately indicates the acidity or alkalinity of a substance.