alcohols

Question 1

alcohols production

Answer 1

hydration
fermentation

Question 2

hydration

Answer 2

Produces alcohols from alkenes in the presence of an acid catalyst
phosphoric acid commonly used as the catalyst under aqueous conditions at 300
high pressure
high percentage yield as ethanol is only product

Question 3

fermentation

Answer 3

enzymes break down starch from crops into sugars ehich can then be fdermented to alc
cheparer
lower temp
fermented in batch
slower
and lower yield

Question 4

oxidation of alchol

Answer 4

alchols can be primary , secondary or tertiary
1 and 2 alchols can be oidsed to produce various products but tertiary alcchols are not easily oxidised

Question 5

how primary alchols identified

Answer 5

primary alcohols can be heated in the presence of acidified potassium dischromate and distilled to produced aldehyde
when heated further under reflx condition ,primary alcohols oxidise further to produce carboxylic acids

Question 6

how secodary alcohols identiies

Answer 6

oxidised when heated in the presence of acidified potassium dichromate to prooduce ketones

Question 7

potassium dischromate

Answer 7

this is used in the oxidation of alcohols as the oxidising agent
it is reduced as the alchol is oxidised
observed as a colour change from orange to green when oxidised

Question 8

Ethanol is produced commercially by fermentation of aqueous glucose, C6H12O6
State two conditions, other than temperature, which are necessary for fermentation.
Explain why neither a low temperature nor a high temperature is suitable for this reaction.
Give two advantages of this method of production over that by the direct hydration of ethene.
Write an equation for the production of ethanol by fermentation and an equation for the complete combustion of ethanol

Answer 8

Condition = two from yeast (anywhere in question)
Air excluded or sterile / clean (2)
Ignore references to pressure / temperature / aqueous / dark / high alcohol conc
Temperature too low inactivates / deactivates enzymes or reaction too slow (1)
Temperature too high destroys or denatures yeast / enzymes (1)
Not kills enzymes; not deactivates here

Advantage 1 = sugar / glucose / carbohydrate is renewable resource / source (1) Advantage 2 = production uses low level technology / cheap equipment (1) Ignore references to energy Do not allow contra-arguments about ethene
C6H12O6  2CH3CH2OH + 2CO2 balanced (1)
C2H5OH +3O2  2CO2 +3H2O balanced (1) Allow C2H6O but penalise C2H5HO once