Find. Which of the five compounds are reasonable candidates for vacuum extraction (soil vapor extraction, SVE) from the vadose zone, based on their octanol-water partition coefficients.
Approach. $K_{ow}$ is a measure of a compound's hydrophobicity, and correlates directly with how strongly it sorbs to soil organic carbon ($K_{oc}\approx0.41\,K_{ow}$): a low $K_{ow}$ means the compound stays weakly bound to the soil and remains available to volatilize into the extracted soil-gas stream, while a high $K_{ow}$ means it partitions strongly onto soil organic matter and resists vapor-phase removal. Published SVE-feasibility screening (EPA, LaGrega et al.) generally treats log $K_{ow}\lesssim3$ as favourable and log $K_{ow}\gtrsim4$ as a poor candidate on sorption grounds alone — but SVE also requires genuine volatility (a high vapor pressure/Henry's constant), which $K_{ow}$ does not directly measure, so each compound is checked against both criteria.
Screen against the log $K_{ow}\lesssim3$ favourable threshold. 2-Butanone, vinyl chloride and phenol all fall below the threshold on sorption grounds; ethyl benzene sits right at the borderline; PCB congeners (6.01) are far above it.
Cross-check volatility (the criterion $K_{ow}$ alone does not capture). Vinyl chloride is a gas at room temperature (very high vapor pressure) — a classic, highly effective SVE target. 2-Butanone (MEK) is a volatile industrial solvent — also volatilizes readily under vacuum. Ethyl benzene is a BTEX aromatic with moderate-to-good volatility and is routinely and successfully targeted by SVE in practice, despite its borderline $K_{ow}$. Phenol, despite its LOW $K_{ow}$, has a comparatively low vapor pressure and very high water solubility — it does not partition readily into the vapor phase, so it is in practice a POOR SVE candidate despite passing the sorption screen; this is the key illustration that $K_{ow}$ alone is necessary but not sufficient. PCB congeners are both strongly sorbed (very high $K_{ow}$) and essentially non-volatile — a clear non-candidate for vacuum extraction by either criterion.
Final results
Compound
log $K_{ow}$
SVE (vacuum extraction) candidate?
2-Butanone (MEK)
0.26
Yes — low sorption, genuinely volatile
Vinyl chloride
1.38
Yes — low sorption, highly volatile (gas)
Phenol
1.46
No — low sorption but poor volatility/high solubility
Ethyl benzene
3.15
Yes (borderline $K_{ow}$, but volatile BTEX aromatic)
PCB congeners
6.01
No — strongly sorbed, essentially non-volatile
Check: candidacy is assessed here using published qualitative volatility knowledge for each named compound alongside the given $K_{ow}$ values, since the source supplies only $K_{ow}$ (a sorption/hydrophobicity metric) and not a Henry's constant or vapor pressure for any compound; this is stated explicitly because $K_{ow}$ alone would otherwise incorrectly flag phenol as a good SVE candidate.
