What is the purpose of the pH scale?

The pH scale serves as a critical tool in chemistry for quantifying the acidity or basicity of a solution. It ranges from 0 to 14, where values below 7 indicate acidic conditions, a value of 7 signifies neutrality, and values above 7 reflect basic or alkaline conditions. This scale is logarithmic, meaning that each whole number change on the scale represents a tenfold change in hydrogen ion concentration. Understanding the pH is essential for a variety of applications, including determining the suitability of water for drinking, assessing soil health for agriculture, and maintaining appropriate conditions in chemical reactions and biological systems.

The other choices, while relevant to different scientific measurements, do not pertain to the fundamental aim of the pH scale. Temperature is measured in degrees, concentration typically refers to the amount of solute in a given volume of solvent, and density is a measure of mass per unit volume. None of these relate to the specific purpose of assessing acidity or basicity, which is the primary function of the pH scale.