Chapter 14: Alcohols (14.1-14.2)

Cn H2n+1 OH

-OH (hydroxyl)

polar O-H bonds (oxygen is more electronegative than hydrogen) therefore hydrogen bonds exist between molecules + there are polar bonds within the molecules

strong hydrogen bonds result in alcohols having relatively high melting/boiling points and low volatility (compared to alkanes of a similar mass)

Soluble in water (solubility decreases as the carbon chain length increases) alcohols can from hydrogen bonds with water molecules, meaning alcohols with a SHORT carbon chain are soluble in water

Primary (-OH group is bonded to a carbon atom that is only attached to 1 other carbon atom) Secondary (-OH group attached to a carbon atom that is attached to 2 other carbon atoms) Tertiary (-OH group attached to a carbon atom that it attached to 3 other carbon atoms)

CO2 (g) + H2O (l)

acidified potassium dichromate(VI) K2Cr2O7/H2SO4 represented as [O] in equation

orange –> green no colour change for tertiary alcohols as they cannot be oxidised

primary alcohol is heated (with oxidising agent) under distillation distilling off the aldehyde prevents furrier oxidation aldehyde: RCHO

primary alcohol is heated under reflux (w excess oxidising agent). Heating under reflux prevents the aldehyde, which initially forms from escaping so that full oxidation can take place and a carboxylic acid is formed. carboxylic acid: RCOOH

secondary alcohol is heated under reflux (with oxidising agent) to form a ketone. Ketones cannot be oxidised further ketone: RCOR

dehydrating agents (e.g. H2SO4 or H3PO4) can be used to remove H2O from alcohols to from an alkene and water

alcohols react with hydrogen-halides in acidic conditions to produce a haloalkane and water. halide ion replaces OH group.