2025 QRC Chemist Evaluation Practice Exam

Gas chromatography is primarily used to separate and analyze volatile compounds, making the choice of B accurate. This technique involves passing a sample through a column that is usually filled with a stationary phase. As the sample moves through the column, different compounds in the mixture interact with the stationary phase to varying degrees, causing them to elute at different times. This separation allows for the identification and quantitative analysis of the individual components, making gas chromatography particularly valuable in fields such as environmental monitoring, food and beverage analysis, and forensics.

The focus on volatile compounds is key; gas chromatography is not suitable for analyzing solid samples directly, nor is it optimized for non-volatile compounds. Consequently, options that involve measuring pH levels, determining molecular weights, or synthesizing compounds do not align with the fundamental principles and applications of gas chromatography.