Look up the boiling points of anisole and d-limonene. which one do you expect to elute first in gas chromotograpjhy

The primary factor that determines the elution order of compounds during gas chromatography, is the boiling point of the compounds. The lower the boiling point of a substance, the shorter retention time the substance will have. The retention time is the time it takes for the substance to be injected into the GC and reach the detector.

A lower boiling compound will elute faster (shorter retention time) than a higher boiling compound. The reason for this is the mobile phase of GC is a gas while the stationary phase is a liquid. Therefore, the more time a compound spends in the mobile phase, the faster it will elute. 

The boiling point of anisole and d-limonene are 153.8 °C and 176 °C, respectively. Therefore, anisole will have a shorter retention time since it has the lower boiling point.

The correct answer is b