ORGANIC CHEMISTRY · PROPERTIES AND EVIDENCE MAP
Connect polarity and phase behavior to laboratory decisions, then read IR, proton NMR, carbon NMR, and multi-spectrum evidence without turning one familiar cue into an unsupported identity claim.
THE EVIDENCE AUDIT
Name the geometry, solvent, phase system, measurement, band, signal, and absence actually supplied.
Add vectors, compute Rf or recovery, resolve protonation state, rank volatility, or count distinct environments.
Keep only conclusions compatible with every positive and negative finding.
Stop before an exact property, pure fraction, unique identity, formula, or full structure that the evidence cannot establish.
NINE CONNECTED EVIDENCE STATIONS
Each station maps to exactly one frozen study objective and contains model, measurement, decision, and boundary records. Together they cover all named evidence cues without inventing cue-level quotas.
Structure · Polarity · General
The two bond dipoles cancel, so this symmetric linear model has zero net molecular dipole.
The vectors add to a nonzero resultant, so the bent molecule is polar.
Symmetric trigonal-planar bond dipoles cancel, giving zero net molecular dipole in the supplied model.
Asymmetric component vectors give a nonzero sum, supporting polarity but not an exact experimental dipole.
Structure · Intermolecular Forces · Melting Point/Boiling Point
Both use dispersion forces; butane's larger framework supports its higher boiling point in this controlled comparison.
Ethanol self-associates by hydrogen bonding, supporting the higher boiling point in this matched pair.
The supplied model ranks n-pentane higher for boiling behavior because its shape permits greater dispersion contact.
The packing evidence supports neopentane as the higher-melting isomer; the boiling order need not be identical.
Structure · Solubility · General
Benzoic acid is predominantly benzoate, so ionization enhances its affinity for the aqueous phase.
Aniline is predominantly protonated as anilinium, so its aqueous affinity is enhanced under these acidic conditions.
The neutral hydrocarbon framework favors the nonpolar organic phase rather than water.
The model ranks butanol above octanol for water solubility because octanol has the longer nonpolar chain.
Laboratory Theory & Techniques · Chromatography · General
The retention factor is 0.50 for this plate and solvent system.
Anisole travels or elutes first, while benzyl alcohol is retained more strongly by polar silica.
Caffeine elutes first in the bounded reverse-phase model, while naphthalene is retained more strongly.
Rf is 0.50, but one TLC value does not uniquely identify the unknown.
Laboratory Theory & Techniques · Extractions · Recrystallization
The dichloromethane organic layer is on the bottom, and the neutral target is collected from that bottom layer.
The ether organic layer is on top, and the neutral target is collected from that top layer.
Benzoate is the dominant ionic state and is transferred preferentially into the aqueous phase before later acid recovery.
The theoretical crystal recovery is 4.00 g, or 80%, before mechanical and handling losses.
Laboratory Theory & Techniques · Distillation · General
Simple distillation is the bounded choice, and the 80 °C product is the first volatile component collected.
Fractional distillation is selected, and the early vapor is enriched in cyclohexane, the lower-boiling component.
Simple distillation is sufficient in the bounded model, and the first fraction is enriched in diethyl ether.
Fractionation can enrich the lower-boiling ethanol side, but ordinary distillation cannot pass the supplied azeotropic limit.
Spectroscopy · Infrared · General
The evidence supports an alcohol functional-group hypothesis and argues against a carbonyl-containing candidate.
The bounded candidates favor a ketone rather than an alcohol or carboxylic acid.
The paired bands support the carboxylic-acid candidate over the ketone, alcohol, or nitrile candidates.
The evidence supports a nitrile functional group while excluding the supplied alcohol and carbonyl candidates.
Spectroscopy · ¹H NMR · ¹³C NMR
Signal count, integration, the triplet–quartet pair, and two carbon environments together support ethanol.
Symmetry, 6:4 integration, triplet–quartet pairing, and two carbon signals support diethyl ether.
One 6H singlet plus two carbon environments, one carbonyl, supports acetone.
Two 3H singlets and three carbon environments support methyl acetate among the bounded candidates.
Spectroscopy · Multi-Spectra · General
All supplied formula, IR, proton, and carbon constraints intersect at 2-butanone.
The complete positive and negative evidence supports butanal rather than the other bounded candidates.
The complete formula, IR, proton, and carbon evidence together supports ethyl acetate.
The complete evidence supports 1-butanol among the bounded candidates.
SOURCES AND LIMITS
The official Structure, Laboratory Theory & Techniques, and Spectroscopy lines—and their named cues—come from the ADA Organic Chemistry specification ↗. The nine-station sequence is DAT TRAIN’s instructional organization, not an ADA frequency claim.
The validators check vector sums, conditional state, Rf, layer density, theoretical recrystallization recovery, bounded distillation choice, spectrum constraints, and complete candidate intersection. They do not establish experimental purity, safety, yield, or multistep route feasibility, which belongs to synthesis practice.