Alcohols

Question 1

Hydration of alkenes

Answer 1

Produces alcohols from alkenes in the presence of an acid catalyst.

Question 2

Hydration of alkenes conditions

Answer 2

Phosphoric acid catalyst under aqueous conditions at 300°C and high pressures

Question 3

Fermentation

Answer 3

Enzymes break down starch into sugars which are fermented into alcohol. Cheaper than hydration as can be carried out at a lower temperature. Slower and lower yield.

Question 4

Conditions for oxidising 1° alcohols

Answer 4

Heated in the presence of acidified potassium dichromate and distilled to form aldehydes. When heated further under reflux conditions, 1° alcohols oxidise further to produce carboxylic acids.

Question 5

Conditions for oxidising 2° alcohols

Answer 5

Heated in the presence of acidified potassium dichromate to produce ketones.

Question 6

Test for alcohols or aldehydes

Answer 6

Potassium dichromate oxidises them to produce aldehyde or carboxylic acid and goes from orange to green.

Question 7

Elimination of alcohols

Answer 7

Alkene formed by dehydration of alcohols where a molecule of water is removed from the molecule.

Question 8

Elimination of alcohols conditions

Answer 8

Excess of hot sulfuric acid is added with aluminium oxide used as a catalyst.

Question 9

Elimination of alcohols reaction

Answer 9

Lone pair on oxygen attacks catalyst H+. H²O+ takes electron from bond to carbon and leaves. H connected to neighbouring carbon gives electron to C-C bond and forms double bond as that hydrogen leaves and reforms the catalyst.