Alcohols – Key Vocabulary & Concepts

A comprehensive set of vocabulary flashcards covering definitions, reactions, tests and industrial processes related to alcohol chemistry, distilled from the lecture’s multiple-choice review.

Fermentation (of sugars)

An exothermic biochemical process in which sugars are converted to ethanol and CO₂ by yeast.

Victor Meyer test

A qualitative test that distinguishes 1°, 2° and 3° alcohols by the colour produced after a series of nitrous-acid reactions (red = 1°, blue = 2°, no colour = 3°).

Pseudonitrol

The blue compound formed from secondary alcohols during the Victor Meyer test.

Blood-red coloration (Victor Meyer)

Indicates a primary alcohol in the Victor Meyer test sequence.

Dimethyl ether (methoxymethane)

The ether that is a structural isomer of ethanol (C₂H₆O).

Diethyl ether

Formed when ethanol is heated with concentrated H₂SO₄ at 160–170 °C (acid-catalysed dehydration).

Secondary alcohol

Class of alcohol that yields a ketone on oxidation with reagents such as acidified KMnO₄ or K₂Cr₂O₇.

Ethene

Obtained by passing ethanol vapour over Al₂O₃ at about 350 °C (intramolecular dehydration).

General formula of alcohols

CₙH₂ₙ₊₁OH (or ROH), where R is an alkyl group.

Glycerol

Propane-1,2,3-triol; a trihydric alcohol used in explosives, cosmetics and pharmaceuticals.

Grain alcohol

Another name for ethyl alcohol produced by fermentation of grains.

Diazotization–hydrolysis

Conversion of a primary amine to the corresponding alcohol using NaNO₂/HCl (HNO₂ in situ).

Inversion (of sucrose)

Acid-catalysed hydrolysis of sucrose to glucose and fructose, changing optical rotation from dextrorotatory to levorotatory.

Dehydrogenation of alcohols on Cu (300 °C)

Primary → aldehyde, secondary → ketone, tertiary → alkene.

Esterification

Reaction of an alcohol with a carboxylic acid (in presence of conc. H₂SO₄) forming an ester and water.

Isopropyl alcohol (propan-2-ol)

Secondary alcohol that oxidises to propanone (acetone) and is called rubbing alcohol.

Hydrogen bonding in alcohols

Intermolecular attraction responsible for high solubility of methanol and ethanol in water.

Absolute alcohol

Nearly 100 % ethanol; obtained from rectified spirit by drying agents such as Mg(OC₂H₅)₂ or CaO followed by distillation.

Acidity order of simple alcohols

Primary > secondary > tertiary, owing to decreasing ability to stabilise the alkoxide ion.

Lucas reagent

Anhyd. ZnCl₂ + conc. HCl; reactivity order with alcohols: 3° > 2° > 1° (forms alkyl chlorides).

Indirect hydration (sulphuric-acid method)

Industrial route that converts propene to isopropyl alcohol via ester formation and hydrolysis; unsuitable for primary alcohols.

Alcohol–ether isomerism

Alcohols (ROH) and ethers (R-O-R') having the same molecular formula but different functional groups (e.g., C₂H₆O).

Iodoform test

Reaction with I₂/NaOH that gives yellow CHI₃ precipitate; positive for ethanol and carbonyls with CH₃CO- group.

Hydroboration–oxidation

Anti-Markovnikov addition of BH₃ to alkenes; propene → 1-propanol after H₂O₂/OH⁻ oxidation.

Rectified spirit

Azeotropic mixture of 95.87 % ethanol and 4.13 % water obtained by fractional distillation of fermented wash.

Common dehydrating agents for ROH

Conc. H₂SO₄, Al₂O₃ and P₂O₅—all remove water from alcohols.

Ethylene glycol

HO-CH₂-CH₂-OH; used as automobile antifreeze due to high boiling point and miscibility with water.

Proof spirit (100 proof)

57.1 % ethanol by volume at 15.5 °C (British system).

Ethers’ lack of reactivity with Na

Compounds like CH₃-O-CH₃ do not release H₂ with sodium because they lack acidic O-H hydrogen.

Lithium aluminium hydride (LiAlH₄)

Powerful reducing agent that converts carboxylic acids (e.g., propanoic acid) to primary alcohols.

Boiling-point order (isomeric alcohols)

1° > 2° > 3° owing to decreased surface area and hydrogen-bonding capability with increased branching.

Pyridinium chlorochromate (PCC)

Mild oxidising agent that converts primary alcohols to aldehydes without over-oxidation to acids.

Blue colour (Victor Meyer)

Characteristic of secondary alcohols during the test sequence.

Nitrolic acid

Red crystalline product formed when a primary alcohol (after oxidation to aldehyde) reacts with nitrous acid in Victor Meyer procedure.

Oxo process (hydroformylation)

Adds CO and H₂ to alkenes, forming aldehydes that are hydrogenated to primary alcohols; suited for large-scale 1° alcohol synthesis.

Wood spirit

Common name for methanol; ingestion may cause blindness or death due to its metabolism to formic acid.

Power alcohol

Motor fuel containing absolute ethanol, gasoline and benzene (approx. 80 : 15 : 5).

Nitroglycerine

Glyceryl trinitrate; explosive liquid known as Nobel’s oil and used in dynamite.

Dynamite

Porous solid (e.g., kieselguhr) saturated with nitroglycerine to stabilise the explosive for safe handling.

Saponification

Alkaline hydrolysis of fats/oils producing glycerol and soaps (sodium or potassium carboxylates).

tert-Butyl alcohol

(CH₃)₃C-OH; exhibits exceptionally high water solubility due to extensive branching despite its four carbon atoms.

Drying of ethanol

Anhydrous CaO or Mg turnings are used; anhydrous CaCl₂ is unsuitable because it forms an alcoholate complex instead of removing water.

¹⁸O-labeling in esterification

Tracer experiment showing that the C-O bond of the acid (acyl-oxygen) remains intact while the alcohol O-H bond is cleaved.

Breathalyser reagent

Acidified K₂Cr₂O₇, which is reduced by ethanol in breath, producing a colour change used to estimate blood-alcohol level.

Rubbing alcohol

Commercial name for 70 % propan-2-ol solution used as a topical antiseptic.