Which electronic instrument is used to measure pH levels of substances?

The pH meter is a specialized electronic instrument designed specifically to measure the acidity or alkalinity of a solution by determining its pH level. It functions by using an electrode that detects the hydrogen ion concentration in the sample, providing a direct reading of pH on its display. This is crucial in various fields, including chemistry, biology, and environmental science, where accurate pH measurement is essential for experiments and analyses.

In contrast, a conductivity meter measures the electrical conductivity of a solution, which can give an indirect indication of ion concentration but does not provide pH values. A spectrophotometer, on the other hand, measures the absorption of light at different wavelengths and is used for identifying and quantifying substances but is not intended for pH measurement. Lastly, an osmometer is used to measure osmotic pressure and is specific to assessing the concentration of solutes in a solution rather than pH levels. Thus, the pH meter is uniquely suited for measuring pH, making it the correct choice.