Final answer:
The most effective method to separate two volatile compounds is distillation (option c.), which leverages differences in their volatilities to accomplish the separation. The option (C) is correct.
Step-by-step explanation:
To most effectively separate two volatile compounds, distillation should be used. Distillation involves heating a mixture to vaporize the most volatile component, which is then condensed back into a liquid and collected separately. This method exploits the different volatilities of the compounds, which is generally the difference in their boiling points. Liquid-liquid extraction may not be as effective because both compounds are volatile, which complicates the separation.
Recrystallization is not suitable for volatile compounds, as this method is typically used for solids. Gas-liquid chromatography, while it could theoretically separate two volatile compounds, is more of a measurement or analytical technique rather than a preparative separation method. Thus, distillation is the most appropriate method among the given options for separating two volatile compounds in a mixture. Therefore, option (C) is correct.