Organic Analysis

Vocabulary flashcards covering tests for alcohols, aldehydes, alkenes, carboxylic acids, and spectroscopy (MS and IR), plus the infrared-driven greenhouse effect.

Acidified potassium dichromate test for alcohols

Identifies 1° and 2° alcohols; orange solution turns green upon oxidation; 3° alcohols are not oxidised (orange remains).

Tollens' test (Tollen’s reagent) for aldehydes

Silver mirror forms on warming if an aldehyde is present; ketones do not react.

Fehling's solution test for aldehydes

Brick red precipitate forms with aldehydes on heating; blue solution remains if absent.

Bromine water test for alkenes

Decolorizes from orange-brown to colorless in the presence of C=C; alkanes unchanged.

Carboxylic acids with sodium carbonate

Acids react to release CO2; CO2 tested by limewater turning cloudy.

Limewater test for CO2

Turns cloudy in the presence of CO2.

Mass spectrometry (MS)

Analytical technique to identify compounds and determine molecular formula.

High Resolution Mass Spectrometry

A more sensitive MS that measures exact masses to several decimal places to deduce molecular formula.

Infrared Spectroscopy (IR)

Technique using IR radiation to identify functional groups by absorption; yields a spectrum with characteristic peaks.

OH stretch – alcohols

IR peak typically 3230–3550 cm⁻¹.

OH stretch – carboxylic acids

IR broad peak around 2500–3000 cm⁻¹.

C=C stretch (unsaturated group)

IR peak typically 1620–1680 cm⁻¹.

C=O stretch (carbonyl group)

IR peak typically 1680–1750 cm⁻¹.

Fingerprint region (IR spectrum)

Right-hand region containing small, unique differences used to identify molecules.

Global warming – infrared absorption

IR absorption by atmospheric molecules traps heat; enhanced by gases like ozone and CFCs due to human activity.