Which type of analysis is performed to evaluate water hardness?

The analysis performed to evaluate water hardness specifically focuses on measuring the concentrations of calcium and magnesium in the water. Water hardness is primarily caused by the presence of these minerals, and their levels dictate the hardness classification of the water, such as soft or hard.

Calcium and magnesium ions interact with soap and other detergents, influencing their effectiveness and how they behave in various applications, from household cleaning to industrial processes. Thus, testing for calcium and magnesium provides direct insight into the hardness of water, making it the standard method for evaluating this property.

Other options are related to different aspects of water quality but do not directly assess hardness. Soil extraction analysis generally pertains to the evaluation of soil components rather than water hardness. Nitrate testing focuses on the presence of nitrates, which are crucial for assessing water quality concerning agricultural runoff and pollution, but do not inform on hardness. Similarly, pH balance assessment measures the acidity or alkalinity of water rather than its hardness. Therefore, the correct choice is grounded in the direct relationship between calcium and magnesium concentrations and water hardness.