Organic Chemistry Functional Group Tests

These flashcards cover key functional group tests and their outcomes in organic chemistry.

Bromine (Br₂/CCI) - decolorizes

Confirms presence of alkenes, alkynes, or oxidized aldehydes; aromatic rings do not react without a catalyst.

Bromine (Br₂/CCI) - no decolorization

Rules out alkenes, alkynes, aldehydes

KMnO (Baeyer's test) - purple to brown/colorless

Confirms oxidizable functional groups: alkene, alkyne, aldehyde, or 1°/2° alcohol.

KMnO4 stays purple

Rules out alkenes, alkynes, aldehydes, and 1°/2° alcohols (no oxidizable functional groups)

Lucas test (ZnCl₂/HCl) - turbidity

Confirms tertiary alcohol (immediate turbidity), secondary alcohol (turbidity in ~5 min), primary alcohol (no reaction at room temp).

Lucas test - no reaction / no turbidity

Rules out tertiary and secondary alcohols; likely a primary alcohol or not an alcohol.

Na metal (sodium) - fizzing

Confirms presence of acidic O-H or N-H

Na metal - no fizzing

Rules out alcohols, carboxylic acids, phenols, primary amines, terminal alkynes; likely an alkane, alkyl halide, ketone, ester, or ether.

Tollens' reagent (Ag⁺/NH₃) - silver mirror

Confirms presence of aldehydes (oxidizes to carboxylate); ketones do not react.

Tollens' - no silver mirror

Rules out aldehydes

NaHCO₃ (bicarbonate) - CO₂ bubbles

Confirms presence of carboxylic acid. Phenols and alcohols do not react.

NaHCO₃ - no bubbles

Rules out carboxylic acids

2,4-DNP (Brady's reagent) - yellow/orange precipitate

Confirms presence of carbonyl group; indicates aldehyde or ketone by forming a colored hydrazone precipitate.

2,4-DNP - no precipitate

Rules out aldehydes and ketones; indicates lack of C=O or that it is an ester/acid, not an aldehyde/ketone.